Long-term changes in migration timing of Song Thrush Turdus philomelos at the southern Baltic coast in response to temperatures on route and at breeding grounds.

Science.gov (United States)

Redlisiak, Michał; Remisiewicz, Magdalena; Nowakowski, Jarosław K

2018-05-26

Climate warming causes the advancement of spring arrival of many migrant birds breeding in Europe, but the effects on their autumn migration are less known. We aimed to determine any changes in the timing of Song Thrush captured during spring and autumn migrations at the Polish Baltic coast from 1975 to 2014, and if these were related to long-term changes of temperature at their breeding grounds and migration routes. The timing of spring migration at Hel ringing station in 1975-2014 did not show long-term advance, but they had responded to environmental conditions on the year-to-year basis. The warmer the temperatures were in April on their migration route, the earlier were the dates of the median and the end of spring migration at Hel. The beginning of autumn migration at the Mierzeja Wiślana ringing station advanced by 5 days between 1975 and 2014. The warmer the April on route, and the July at the Song Thrushes' breeding grounds, the earlier young birds began autumn migration across the Baltic coast. We suggest this was a combined effect of adults' migration and breeding early during warm springs and young birds getting ready faster for autumn migration during warm summers. The average time span of 90% of the autumn migration was extended by 5 days, probably because of early migration of young birds from first broods and late of those from second broods enabled by warm springs and summers. The response of Song Thrushes' migration timing to temperatures on route and at the breeding grounds indicated high plasticity in the species and suggested it might adapt well to climate changes.

Migration routes and staging areas of trans-Saharan Turtle Doves appraised from light-level geolocators.

Directory of Open Access Journals (Sweden)

Cyril Eraud

Full Text Available The identification of migration routes, wintering grounds and stopover sites are crucial issues for the understanding of the Palearctic-African bird migration system as well as for the development of relevant conservation strategies for trans-Saharan migrants. Using miniaturized light-level geolocators we report a comprehensive and detailed year round track of a granivorous trans-Saharan migrant, the European Turtle Dove (Streptopelia turtur. From five recovered loggers, our data provide new insights on migratory journeys and winter destinations of Turtle Doves originating from a breeding population in Western France. Data confirm that Turtle Doves wintered in West Africa. The main wintering area encompassed Western Mali, the Inner Delta Niger and the Malian/Mauritanian border. Some individuals also extended their wintering ranges over North Guinea, North-West of Burkina Faso and the Ivory-Coast. Our results reveal that all individuals did not spend the winter period at a single location; some of them experienced a clear eastward shift of several hundred kilometres. We also found evidence for a loop migration pattern, with a post-breeding migration flyway lying west of the spring route. Finally, we found that on their way back to breeding grounds Turtle Doves needed to refuel after crossing the Sahara desert. Contrary to previous suggestions, our data reveal that birds used stopover sites for several weeks, presumably in Morocco and North Algeria. This later finding is a crucial issue for future conservation strategies because environmental conditions on these staging areas might play a pivotal role in population dynamics of this declining species.

Route optimisation and solving Zermelo’s navigation problem during long distance migration in cross flows

DEFF Research Database (Denmark)

Hays, Graeme C.; Christensen, Asbjørn; Fossette, Sabrina

2014-01-01

The optimum path to follow when subjected to cross flows was first considered over 80 years ago by the German mathematician Ernst Zermelo, in the context of a boat being displaced by ocean currents, and has become known as the ‘Zermelo navigation problem’. However, the ability of migrating animals...... to solve this problem has received limited consideration, even though wind and ocean currents cause the lateral displacement of flyers and swimmers, respectively, particularly during long-distance journeys of 1000s of kilometres. Here, we examine this problem by combining long-distance, open-ocean marine...... not follow the optimum (Zermelo's) route. Even though adult marine turtles regularly complete incredible long-distance migrations, these vertebrates primarily rely on course corrections when entering neritic waters during the final stages of migration. Our work introduces a new perspective in the analysis...

Two convergent routes to the left-wing fragment of ciguatoxin CTX3C using O,S-acetals as key intermediates.

Science.gov (United States)

Inoue, Masayuki; Yamashita, Shuji; Ishihara, Yuuki; Hirama, Masahiro

2006-12-07

Ciguatoxins, principal causative toxins of ciguatera seafood poisoning, are large ladderlike polycyclic ethers. Here, we report two convergent routes to synthesis of the multiolefinic left half of ciguatoxins based on a newly developed acyl radical strategy. Remarkably, only 13 steps from the monocyclic E-ring were required to construct the left wing. [reaction: see text

Building the giant planet cores by convergent migration of pebble-accreting embryos

Science.gov (United States)

Chrenko, Ondrej; Broz, Miroslav

2016-10-01

An explanation of the accretion buildup of giant planet cores on rather short (~Myr) time scales remains a long-standing challenge for scenarios of planetary system formation. One of the recently proposed processes that can take part during this evolutionary stage is the convergent Type I migration of Earth-sized embryos towards the zero-torque radius, occurring at an opacity transition within the dusty-gaseous protoplanetary disk (e.g. Pierens et al. 2013). Inconveniently, simulations show that such groups of embryos do not merge easily because they often get locked in mutual mean-motion resonances and consequently form an inward-migrating convoy.We revise this possibility of merging embryos while taking into account their ongoing growth by pebble accretion. Our aim is to check whether the rapid changes of masses combined with the migration of embryos through the feeding zone can break the resonant chain and allow for the giant planet core formation.The environment of the protoplanetary disk is modeled with the 2D FARGO code (Masset 2000), which we modified in order to perform non-isothermal hydrodynamic simulations, assuming flux-limited radiative diffusion (Levermore & Pomraning 1981). The embedded massive bodies are evolved simultaneously in 3D using the hybrid Wisdom-Holman/Gauss-Radau integrator from the Rebound package (Rein & Spiegel 2015). A semi-analytic method is used to evolve the masses of embryos by pebble accretion (e.g. Levison et al. 2015).

Fall migration routes, timing, and wintering sites of North American ospreys as determined by satellite telemetry

Science.gov (United States)

Martell, M.S.; Henny, Charles J.; Nye, P.; Solensky, Matthew J.

2001-01-01

Satellite telemetry was used to determine fall migratory movements of Ospreys (Pandion haliaetus) breeding in the United States. Study areas were established along the lower Columbia River between Oregon and Washington; in north-central Minnesota; on Shelter Island, New York; and in southern New Jersey. Seventy-four adults (25 males, 49 females) were tracked from 1995 through 1999. Migration routes differed among populations but not by sex. Western Ospreys migrated through California and to a lesser degree other western states and wintered in Mexico (88%), El Salvador (6%), and Honduras (6%) (25.9A?N to 13.0A?N and 108.3A?W to 87.3A?W). Minnesota Ospreys migrated along three routes: (1) through the Central U.S. and then along the east coast of Mexico, (2) along the Mississippi River Valley, then across the Gulf of Mexico, or (3) through the southeastern U.S., then across the Caribbean. East Coast birds migrated along the eastern seaboard of the U.S., through Florida, and across the Caribbean. Midwestern birds wintered from Mexico south to Bolivia (22.35A?N to 13.64A?S, and 91.75A?W to 61.76A?W), while East Coast birds wintered from Florida to as far south as Brazil (27.48A?N to 18.5A?S and 80.4A?W to 57.29A?W). Dates of departure from breeding areas differed significantly between sexes and geographic regions, with females leaving earlier than males. Western birds traveled a shorter distance than either midwestern or eastern Ospreys. Females traveled farther than males from the same population, which resulted in females typically wintering south of males.

Route Fidelity during Marine Megafauna Migration

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Travis W. Horton

2017-12-01

Full Text Available The conservation and protection of marine megafauna require robust knowledge of where and when animals are located. Yet, our ability to predict animal distributions in space and time remains limited due to difficulties associated with studying elusive animals with large home ranges. The widespread deployment of satellite telemetry technology creates unprecedented opportunities to remotely monitor animal movements and to analyse the spatial and temporal trajectories of these movements from a variety of geophysical perspectives. Reproducible patterns in movement trajectories can help elucidate the potential mechanisms by which marine megafauna navigate across vast expanses of open-ocean. Here, we present an empirical analysis of humpback whale (Megaptera novaeangliae, great white shark (Carcharodon carcharias, and northern elephant seal (Mirounga angustirostris satellite telemetry-derived route fidelity movements in magnetic and gravitational coordinates. Our analyses demonstrate that: (1 humpback whales, great white sharks and northern elephant seals are capable of performing route fidelity movements across millions of square kilometers of open ocean with a spatial accuracy of better than 150 km despite temporal separations as long as 7 years between individual movements; (2 route fidelity movements include significant (p < 0.05 periodicities that are comparable in duration to the lunar cycles and semi-cycles; (3 latitude and bedrock-dependent gravitational cues are stronger predictors of route fidelity movements than spherical magnetic coordinate cues when analyzed with respect to the temporally dependent moon illumination cycle. We further show that both route fidelity and non-route fidelity movement trajectories, for all three species, describe overlapping in-phase or antiphase sinusoids when individual movements are normalized to the gravitational acceleration present at migratory departure sites. Although these empirical results provide an

Wind effects on the migration routes of trans-Saharan soaring raptors: geographical, seasonal, and interspecific variation

Science.gov (United States)

Vidal-Mateo, Javier; Mellone, Ugo; López-López, Pascual; La Puente, Javier De; García-Ripollés, Clara; Bermejo, Ana; Urios, Vicente

2016-01-01

Abstract Wind is among the most important environmental factors shaping birds’ migration patterns. Birds must deal with the displacement caused by crosswinds and their behavior can vary according to different factors such as flight mode, migratory season, experience, and distance to goal areas. Here we analyze the relationship between wind and migratory movements of three raptor species which migrate by soaring–gliding flight: Egyptian vulture Neophron percnopterus, booted eagle Aquila pennata, and short-toed snake eagle Circaetus gallicus. We analyzed daily migratory segments (i.e., the path joining consecutive roosting locations) using data recorded by GPS satellite telemetry. Daily movements of Egyptian vultures and booted eagles were significantly affected by tailwinds during both autumn and spring migrations. In contrast, daily movements of short-toed eagles were only significantly affected by tailwinds during autumn migration. The effect of crosswinds was significant in all cases. Interestingly, Egyptian vultures and booted eagles showed latitudinal differences in their behavior: both species compensated more frequently at the onset of autumn migration and, at the end of the season when reaching their wintering areas, the proportion of drift segments was higher. In contrast, there was a higher drift at the onset of spring migration and a higher compensation at the end. Our results highlight the effect of wind patterns on the migratory routes of soaring raptors, with different outcomes in relation to species, season, and latitude, ultimately shaping the loop migration patterns that current tracking techniques are showing to be widespread in many long distance migrants. PMID:29491895

Distinctive and selective route of PI3K/PKCα-PKCδ/RhoA-Rac1 signaling in osteoclastic cell migration.

Science.gov (United States)

Kim, Jin-Man; Kim, Mi Yeong; Lee, Kyunghee; Jeong, Daewon

2016-12-05

Cell migration during specialized stages of osteoclast precursors, mononuclear preosteoclasts, and multinucleated mature osteoclasts remain uncertain. M-CSF- and osteopontin-induced osteoclastic cell migration was inhibited by function-blocking monoclonal antibodies specific to the integrin αv and β3 subunits, suggesting that integrin αvβ3 mediates migratory signaling induced by M-CSF and osteopontin. M-CSF and osteopontin stimulation was shown to regulate two branched signaling processes, PI3K/PKCα/RhoA axis and PI3K/PKCδ/Rac1 axis. Interestingly, inactivation of RhoA or Rac1 blocked preosteoclast and mature osteoclast migration but not osteoclast precursor migration in a transwell-based cell migration assay. Moreover, the inhibitory effect on preosteoclast and mature osteoclast migration induced by Rac1 inactivation was more effective than that by RhoA inactivation. Collectively, our findings suggest that osteoclast precursor migration depends on PI3K/PKCα-PKCδ signaling mediated via integrin αvβ3 bypassing RhoA and Rac1, whereas preosteoclast and mature osteoclast migration relies on PI3K/PKCα-PKCδ/RhoA-Rac1 axis signaling mediated via integrin αvβ3 with increased dependency on PKCδ/Rac1 signaling route as differentiation progresses. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Integrating meteorology into research on migration

NARCIS (Netherlands)

Shamoun-Baranes, J.; Bouten, W.; van Loon, E.E.

2010-01-01

Atmospheric dynamics strongly influence the migration of flying organisms. They affect, among others, the onset, duration and cost of migration, migratory routes, stop-over decisions, and flight speeds en-route. Animals move through a heterogeneous environment and have to react to atmospheric

Migration: the trends converge.

Science.gov (United States)

1985-09-01

Formerly, Australia, New Zealand, Canada, and the US have served as permanent destinations for immigrants, while Europe's migrants have moved to more northerly countries to work for a time and then returned home. From 1973-1975 Europe's recruitment of foreign workers virtually ended, although family reunion for those immigrants allowed in was encouraged. Problems resulting from this new settlement migration include low paying jobs for immigrant women, high unemployment, and inadequate education for immigrant children. Illegal migrants from Latin America and the Caribbean enter the US and Canada each year while illegal North African immigrants enter Italy, Spain, and Greece. North America, Australia, and Europe have all received political refugees from Asia and Latin America. Increasingly, these foreigners compete in the labor market rather than simply fill jobs the native workers do not want. All the receiving countries have similar policy priorities: 1) more effective ways for controlling and monitoring inflows and checking illegal immigration; 2) encouraging normal living patterns and accepting refugees; and 3) integrating permanent migrants into the host country. Europe's public immigration encouragement prior to the first oil shock, has left some countries with a labor force that is reluctant to return home. It is unlikely that Europe will welcome foreign labor again in this decade, since unemployment among young people and women is high and family reunion programs may still bring in many immigrants. Less immigration pattern change will probably occur in North America, Australia, and New Zealand since these countries' populations are still growing and wages are more flexible. Immigration, regulated by policy, and emigration, determined by market forces, now are working in the same direction and will likely reduce future migration flows.

Diversity in destinations, routes and timing of small adult and sub-adult striped bass Morone saxatilis on their southward autumn migration

Science.gov (United States)

Mather, Martha E.; Finn, John T.; Pautzke, Sarah M.; Fox, Dewayne A.; Savoy, Tom; Brundage, Harold M.; Deegan, Linda A.; Muth, Robert M.

2010-01-01

Almost three-quarters of the 46 young adult and sub-adult striped bass Morone saxatilis that were acoustically tagged in Plum Island Estuary, Massachusetts, U.S.A., in the summer of 2006 were detected in one or more southern coastal arrays during their autumn migration. On the basis of the trajectories along which these M. saxatilis moved from feeding to overwintering areas, three migratory groups emerged. After leaving Plum Island Estuary, about half of the fish were detected only in a mid-latitude array, Long Island Sound. The other half of the tagged fish were detected during autumn and winter in a more southern array, the Delaware Estuary. This latter group of fish may have used two routes. Some travelled to the Delaware Estuary through Long Island Sound while other fish may have taken a second, more direct, coastal route that did not include Long Island Sound. Consequently, a seemingly homogeneous group of fish tagged at the same time in the same non-natal feeding location exhibited a diversity of southward movement patterns that could affect population-level processes. These three groups that differed in overwintering location and migration route could be movement contingents with migratory connectivity.

Use of electrical tomography methods to determinate the extension and main migration routes of uncontrolled landfill leachates in fractured areas

Energy Technology Data Exchange (ETDEWEB)

Casado, Ismael, E-mail: iscaferr@gmail.com [Department of Petrology, Geochemistry and Geological Prospectio, Universitat de Barcelona, Martí i Franquès s/n, 08030 Barcelona (Spain); Department of Geology and Environmental Earth Science, Miami University, 501 East High Street, 45056 Oxford, OH (United States); Mahjoub, Himi [Department of Petrology, Geochemistry and Geological Prospectio, Universitat de Barcelona, Martí i Franquès s/n, 08030 Barcelona (Spain); Ecole Nationale des Sciences Appliquées d' Al Hoceima (ENSAH), University Mohammed Premier, Ajdir, Al Hoceima (Morocco); Lovera, Raul [Department of Petrology, Geochemistry and Geological Prospectio, Universitat de Barcelona, Martí i Franquès s/n, 08030 Barcelona (Spain); Fernández, Jesús, E-mail: jfernandezc@aragon.es [Department of Agriculture, Ranching and Environment, Diputación General de Aragon (DGA), Plaza de San Pedro Nolasco, 7, 50071 Zaragoza (Spain); Casas, Albert [Department of Petrology, Geochemistry and Geological Prospectio, Universitat de Barcelona, Martí i Franquès s/n, 08030 Barcelona (Spain)

2015-02-15

This study focuses on the uses of the electrical tomography and its relationship with hydrochemical data in order to characterize contaminated groundwater flows in fractured aquifers. The studied area is contaminated with different hazardous substances like lyndanes, organochlorinated compounds and benzenes coming from the old non-controlled Sardas landfill. The enormous volumes of wastes filling the landfill have generated a convoluted mixture of leachates. Due to the lack of a landfill liner, the leachates have migrated through the fractured Eocene marls towards the Gallego River. The striking correlation between high concentrations of polluted groundwater and low electrical resistivity of the subsurface (< 8 Ω·m) allows defining the principal contaminant migration route thanks to the distribution of these conductive anomalies. This mapping verifies that there is intense tectonical–structural control of the leachate migration, because the deep migration presents the same direction as the geological axis fold. - Highlights: • The outcrop topographic reconstruction is done using cores and aerial photographs. • Hydrochemical and geophysical data allow defining two leachate migration paths. • Conductive anomalies in ERT are linked to high contaminant concentration. • The distribution of conductive anomalies defines the fractured basement migration. • The plume direction reflects important tectonic control in the migration process.

Modelling the secular evolution of migrating planet pairs

Science.gov (United States)

Michtchenko, T. A.; Rodríguez, A.

2011-08-01

The subject of this paper is the secular behaviour of a pair of planets evolving under dissipative forces. In particular, we investigate the case when dissipative forces affect the planetary semimajor axes and the planets move inwards/outwards the central star, in a process known as planet migration. To perform this investigation, we introduce fundamental concepts of conservative and dissipative dynamics of the three-body problem. Based on these concepts, we develop a qualitative model of the secular evolution of the migrating planetary pair. Our approach is based on the analysis of the energy and the orbital angular momentum exchange between the two-planet system and an external medium; thus no specific kind of dissipative forces is invoked. We show that, under the assumption that dissipation is weak and slow, the evolutionary routes of the migrating planets are traced by the Mode I and Mode II stationary solutions of the conservative secular problem. The ultimate convergence and the evolution of the system along one of these secular modes of motion are determined uniquely by the condition that the dissipation rate is sufficiently smaller than the proper secular frequency of the system. We show that it is possible to reassemble the starting configurations and the migration history of the systems on the basis of their final states and consequently to constrain the parameters of the physical processes involved.

DRO: domain-based route optimization scheme for nested mobile networks

Directory of Open Access Journals (Sweden)

Chuang Ming-Chin

2011-01-01

Full Text Available Abstract The network mobility (NEMO basic support protocol is designed to support NEMO management, and to ensure communication continuity between nodes in mobile networks. However, in nested mobile networks, NEMO suffers from the pinball routing problem, which results in long packet transmission delays. To solve the problem, we propose a domain-based route optimization (DRO scheme that incorporates a domain-based network architecture and ad hoc routing protocols for route optimization. DRO also improves the intra-domain handoff performance, reduces the convergence time during route optimization, and avoids the out-of-sequence packet problem. A detailed performance analysis and simulations were conducted to evaluate the scheme. The results demonstrate that DRO outperforms existing mechanisms in terms of packet transmission delay (i.e., better route-optimization, intra-domain handoff latency, convergence time, and packet tunneling overhead.

An Institutional Approach to Bordering in Islands: The Canary Islands on the African-European Migration Routes

Directory of Open Access Journals (Sweden)

Dirk Godenau

2012-05-01

Full Text Available Islands play a significant role in international irregular maritime migration. Frequently they are part of maritime interstitial spaces between states, and their location, combined with institutional membership, makes them part of international migration routes and subject to border management strategies. In this paper borders are analysed as social institutions used for regulating relative permeability through rules of entry and exit for persons, goods and capital. Borders institutionalize territoriality and are politically implemented by states. They are selective, also in migration, and irregular border transit is not always indicative of an inability to control. The Canary Islands are used as an illustrative example of how border management at the southern edge of the European Union has evolved towards more coercive deterrence and tighter surveillance. The Canary Islands experienced irregular maritime immigration from the west African coasts during the first decade of the 21st century and most of these migrants intended to use the islands as transit space towards the European continent. Increasing surveillance in countries of origin, enforcement of border controls and stricter return policies were used to stop flows. The so-called “cayuco crisis” in 2006 induced institutional change in border management and forced the active involvement of the EU through FRONTEX.

On the Convergence of Biogeography-Based Optimization for Binary Problems

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Haiping Ma

2014-01-01

Full Text Available Biogeography-based optimization (BBO is an evolutionary algorithm inspired by biogeography, which is the study of the migration of species between habitats. A finite Markov chain model of BBO for binary problems was derived in earlier work, and some significant theoretical results were obtained. This paper analyzes the convergence properties of BBO on binary problems based on the previously derived BBO Markov chain model. Analysis reveals that BBO with only migration and mutation never converges to the global optimum. However, BBO with elitism, which maintains the best candidate in the population from one generation to the next, converges to the global optimum. In spite of previously published differences between genetic algorithms (GAs and BBO, this paper shows that the convergence properties of BBO are similar to those of the canonical GA. In addition, the convergence rate estimate of BBO with elitism is obtained in this paper and is confirmed by simulations for some simple representative problems.

WLCI researchers employ new approaches to help managers conserve deer migrations

Science.gov (United States)

Allen, Leslie A.; Kauffman, Matthew J.

2012-01-01

Elk, mule deer, pronghorn antelope, moose, and bighorn sheep are iconic animals of the American West. These hooved animals, known as ungulates, commonly travel 30–60 miles between seasonal ranges. These migrations between winter and summer ranges are vital for survival and reproduction. As habitat fragmentation continues, the conservation of ungulate migration routes has received considerable attention in the West and across the globe. For example, it is estimated that many ungulate migration routes in the Greater Yellowstone Ecosystem have already been lost. The traditional migration routes of Wyoming ungulates are threatened by unprecedented levels of energy development and by increasing levels of rural ranchette development (including fences, structures, and roads). In the past, migration corridors have been mapped based primarily on the expert opinions of state game managers, but long-term conservation of Wyoming's ungulate migration routes requires a better understanding of migration ecology and more sophisticated management tools. Wyoming Landscape Conservation Initiative (WLCI) researchers investigated the migration of a large mule deer herd across the Dad and Wild Horse winter ranges in southwest Wyoming, where 2,000 gas wells and 1,609 kilometers of pipelines and roads have been proposed for development.

Does Migration Influence Regional Growth in Romania?

OpenAIRE

Bunea Daniela

2011-01-01

In the European framework, regional convergence is crucial in ensuring European integration. “Sigma-convergence” deals with how the distribution of national output across economies evolves over time whereas “beta-convergence” deals with the mobility of this output within the same distribution. Migration is one important mechanism in generating convergence. In Romania, during the last few years, the main results point out at an income divergence trend with no migration influence. This irreleva...

Walkable Route Perceptions and Physical Features: Converging Evidence for En Route Walking Experiences

Science.gov (United States)

Brown, Barbara B.; Werner, Carol M.; Amburgey, Jonathan W.; Szalay, Caitlin

2007-01-01

Guided walks near a light rail stop in downtown Salt Lake City, Utah, were examined using a 2 (gender) x 3 (route walkability: low-mixed-, or high-walkability features) design. Trained raters confirmed that more walkable segments had more traffic, environmental, and social safety; pleasing aesthetics; natural features; pedestrian amenities; and…

Records of Migration in the Exoplanet Configurations

Science.gov (United States)

Michtchenko, Tatiana A.; Rodriguez Colucci, A.; Tadeu Dos Santos, M.

2013-05-01

Abstract (2,250 Maximum Characters): When compared to our Solar System, many exoplanet systems exhibit quite unusual planet configurations; some of these are hot Jupiters, which orbit their central stars with periods of a few days, others are resonant systems composed of two or more planets with commensurable orbital periods. It has been suggested that these configurations can be the result of a migration processes originated by tidal interactions of the planets with disks and central stars. The process known as planet migration occurs due to dissipative forces which affect the planetary semi-major axes and cause the planets to move towards to, or away from, the central star. In this talk, we present possible signatures of planet migration in the distribution of the hot Jupiters and resonant exoplanet pairs. For this task, we develop a semi-analytical model to describe the evolution of the migrating planetary pair, based on the fundamental concepts of conservative and dissipative dynamics of the three-body problem. Our approach is based on an analysis of the energy and the orbital angular momentum exchange between the two-planet system and an external medium; thus no specific kind of dissipative forces needs to be invoked. We show that, under assumption that dissipation is weak and slow, the evolutionary routes of the migrating planets are traced by the stationary solutions of the conservative problem (Birkhoff, Dynamical systems, 1966). The ultimate convergence and the evolution of the system along one of these modes of motion are determined uniquely by the condition that the dissipation rate is sufficiently smaller than the roper frequencies of the system. We show that it is possible to reassemble the starting configurations and migration history of the systems on the basis of their final states, and consequently to constrain the parameters of the physical processes involved.

New Insights on Water Buffalo Genomic Diversity and Post-Domestication Migration Routes From Medium Density SNP Chip Data

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Licia Colli

2018-03-01

Full Text Available The domestic water buffalo is native to the Asian continent but through historical migrations and recent importations, nowadays has a worldwide distribution. The two types of water buffalo, i.e., river and swamp, display distinct morphological and behavioral traits, different karyotypes and also have different purposes and geographical distributions. River buffaloes from Pakistan, Iran, Turkey, Egypt, Romania, Bulgaria, Italy, Mozambique, Brazil and Colombia, and swamp buffaloes from China, Thailand, Philippines, Indonesia and Brazil were genotyped with a species-specific medium-density 90K SNP panel. We estimated the levels of molecular diversity and described population structure, which revealed historical relationships between populations and migration events. Three distinct gene pools were identified in pure river as well as in pure swamp buffalo populations. Genomic admixture was seen in the Philippines and in Brazil, resulting from importations of animals for breed improvement. Our results were largely consistent with previous archeological, historical and molecular-based evidence for two independent domestication events for river- and swamp-type buffaloes, which occurred in the Indo-Pakistani region and close to the China/Indochina border, respectively. Based on a geographical analysis of the distribution of diversity, our evidence also indicated that the water buffalo spread out of the domestication centers followed two major divergent migration directions: river buffaloes migrated west from the Indian sub-continent while swamp buffaloes migrated from northern Indochina via an east-south-eastern route. These data suggest that the current distribution of water buffalo diversity has been shaped by the combined effects of multiple migration events occurred at different stages of the post-domestication history of the species.

Iconic memory-based omnidirectional route panorama navigation.

Science.gov (United States)

Yagi, Yasushi; Imai, Kousuke; Tsuji, Kentaro; Yachida, Masahiko

2005-01-01

A route navigation method for a mobile robot with an omnidirectional image sensor is described. The route is memorized from a series of consecutive omnidirectional images of the horizon when the robot moves to its goal. While the robot is navigating to the goal point, input is matched against the memorized spatio-temporal route pattern by using dual active contour models and the exact robot position and orientation is estimated from the converged shape of the active contour models.

Modelling larval transport in a axial convergence front

Science.gov (United States)

Robins, P.

2010-12-01

Marine larvae exhibit different vertical swimming behaviours, synchronised by factors such as tidal currents and daylight, in order to aid retention near the parent populations and hence promote production, avoid predation, or to stimulate digestion. This paper explores two types of larval migration in an estuarine axial convergent front which is an important circulatory mechanism in many coastal regions where larvae are concentrated. A parallelised, three-dimensional, ocean model was applied to an idealised estuarine channel which was parameterised from observations of an axial convergent front which occurs in the Conwy Estuary, U.K. (Nunes and Simpson, 1985). The model successfully simulates the bilateral cross-sectional recirculation of an axial convergent front, which has been attributed to lateral density gradients established by the interaction of the lateral shear of the longitudinal currents with the axial salinity gradients. On the flood tide, there is surface axial convergence whereas on the ebb tide, there is (weaker) surface divergence. Further simulations with increased/decreased tidal velocities and with stronger/weaker axial salinity gradients are planned so that the effects of a changing climate on the secondary flow can be understood. Three-dimensional Lagrangian Particle Tracking Models (PTMs) have been developed which use the simulated velocity fields to track larvae in the estuarine channel. The PTMs take into account the vertical migrations of two shellfish species that are commonly found in the Conwy Estuary: (i) tidal migration of the common shore crab (Carcinus maenas) and (ii), diel (daily) migration of the Great scallop (Pecten maximus). These migration behaviours are perhaps the most widespread amongst shellfish larvae and have been compared with passive (drifting) particles in order to assess their relative importance in terms of larval transport. Preliminary results suggest that the net along-estuary dispersal over a typical larval

Introducing radiality constraints in capacitated location-routing problems

Directory of Open Access Journals (Sweden)

Eliana Mirledy Toro Ocampo

2017-03-01

Full Text Available In this paper, we introduce a unified mathematical formulation for the Capacitated Vehicle Routing Problem (CVRP and for the Capacitated Location Routing Problem (CLRP, adopting radiality constraints in order to guarantee valid routes and eliminate subtours. This idea is inspired by formulations already employed in electric power distribution networks, which requires a radial topology in its operation. The results show that the proposed formulation greatly improves the convergence of the solver.

Biodistribution of radiolabelled human dendritic cells injected by various routes

International Nuclear Information System (INIS)

Quillien, Veronique; Moisan, Annick; Carsin, Andre; Lesimple, Thierry; Lefeuvre, Claudia; Bertho, Nicolas; Devillers, Anne; Toujas, Louis; Adamski, Henri; Leberre, Claudine

2005-01-01

The purpose of this study was to investigate the biodistribution of mature dendritic cells (DCs) injected by various routes, during a cell therapy protocol. In the context of a vaccine therapy protocol for melanoma, DCs matured with Ribomunyl and interferon-gamma were labelled with 111 In-oxine and injected into eight patients along various routes: afferent lymphatic vessel (IL) (4 times), lymph node (IN) (5 times) and intradermally (ID) (6 times). Scintigraphic investigations showed that the IL route allowed localisation of 80% of injected radioactivity in eight to ten nodes. In three cases of IN injection, the entire radioactivity stagnated in the injected nodes, while in two cases, migration to adjacent nodes was observed. This migration was detected rapidly after injection, as with IL injections, suggesting that passive transport occurred along the physiological lymphatic pathways. In two of the six ID injections, 1-2% of injected radioactivity reached a proximal lymph node. Migration was detectable in the first hour, but increased considerably after 24 h, suggesting an active migration mechanism. In both of the aforementioned cases, DCs were strongly CCR7-positive, but this feature was not a sufficient condition for effective migration. In comparison with DCs matured with TNF-α, IL-1β, IL-6 and PGE2, our DCs showed a weaker in vitro migratory response to CCL21, despite comparable CCR7 expression, and higher allostimulatory and TH1 polarisation capacities. The IL route allowed reproducible administration of specified numbers of DCs. The IN route sometimes yielded fairly similar results, but not reproducibly. Lastly, we showed that DCs matured without PGE2 that have in vitro TH1 polarisation capacities can migrate to lymph nodes after ID injection. (orig.)

Plane-wave Least-squares Reverse Time Migration

KAUST Repository

Dai, Wei; Schuster, Gerard T.

2012-01-01

convergence for least-squares migration even when the migration velocity is not completely accurate. To significantly reduce computation cost, linear phase shift encoding is applied to hundreds of shot gathers to produce dozens of planes waves. A

Integrating meteorology into research on migration.

Science.gov (United States)

Shamoun-Baranes, Judy; Bouten, Willem; van Loon, E Emiel

2010-09-01

Atmospheric dynamics strongly influence the migration of flying organisms. They affect, among others, the onset, duration and cost of migration, migratory routes, stop-over decisions, and flight speeds en-route. Animals move through a heterogeneous environment and have to react to atmospheric dynamics at different spatial and temporal scales. Integrating meteorology into research on migration is not only challenging but it is also important, especially when trying to understand the variability of the various aspects of migratory behavior observed in nature. In this article, we give an overview of some different modeling approaches and we show how these have been incorporated into migration research. We provide a more detailed description of the development and application of two dynamic, individual-based models, one for waders and one for soaring migrants, as examples of how and why to integrate meteorology into research on migration. We use these models to help understand underlying mechanisms of individual response to atmospheric conditions en-route and to explain emergent patterns. This type of models can be used to study the impact of variability in atmospheric dynamics on migration along a migratory trajectory, between seasons and between years. We conclude by providing some basic guidelines to help researchers towards finding the right modeling approach and the meteorological data needed to integrate meteorology into their own research. © The Author 2010. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved.

Structural and temporal requirements of Wnt/PCP protein Vangl2 function for convergence and extension movements and facial branchiomotor neuron migration in zebrafish.

Science.gov (United States)

Pan, Xiufang; Sittaramane, Vinoth; Gurung, Suman; Chandrasekhar, Anand

2014-02-01

Van gogh-like 2 (Vangl2), a core component of the Wnt/planar cell polarity (PCP) signaling pathway, is a four-pass transmembrane protein with N-terminal and C-terminal domains located in the cytosol, and is structurally conserved from flies to mammals. In vertebrates, Vangl2 plays an essential role in convergence and extension (CE) movements during gastrulation and in facial branchiomotor (FBM) neuron migration in the hindbrain. However, the roles of specific Vangl2 domains, of membrane association, and of specific extracellular and intracellular motifs have not been examined, especially in the context of FBM neuron migration. Through heat shock-inducible expression of various Vangl2 transgenes, we found that membrane associated functions of the N-terminal and C-terminal domains of Vangl2 are involved in regulating FBM neuron migration. Importantly, through temperature shift experiments, we found that the critical period for Vangl2 function coincides with the initial stages of FBM neuron migration out of rhombomere 4. Intriguingly, we have also uncovered a putative nuclear localization motif in the C-terminal domain that may play a role in regulating CE movements. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Modeling the secular evolution of migrating planet pairs

Science.gov (United States)

Michtchenko, T. A.; Rodríguez, A.

2011-10-01

The secular regime of motion of multi-planetary systems is universal; in contrast with the 'accidental' resonant motion, characteristic only for specific configurations of the planets, secular motion is present everywhere in phase space, even inside the resonant region. The secular behavior of a pair of planets evolving under dissipative forces is the principal subject of this study, particularly, the case when the dissipative forces affect the planetary semi-major axes and the planets move inward/outward the central star, the process known as planet migration. Based on the fundamental concepts of conservative and dissipative dynamics of the three-body problem, we develop a qualitative model of the secular evolution of the migrating planetary pair. Our approach is based on analysis of the energy and the orbital angular momentum exchange between the two-planet system and an external medium; thus no specific kind of dissipative forces is invoked. We show that, under assumption that dissipation is weak and slow, the evolutionary routes of the migrating planets are traced by the Mode I and Mode II stationary solutions of the conservative secular problem. The ultimate convergence and the evolution of the system along one of these secular modes of motion is determined uniquely by the condition that the dissipation rate is sufficiently smaller than the proper secular frequency of the system. We show that it is possible to reassemble the starting configurations and migration history of the systems on the basis of their final states and consequently to constrain the parameters of the physical processes involved.

Migration and growth of protoplanetary embryos. I. Convergence of embryos in protoplanetary disks

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaojia; Lin, Douglas N. C. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Liu, Beibei [Kavli Institute for Astronomy and Astrophysics and Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Li, Hui, E-mail: xzhang47@ucsc.edu [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2014-12-10

According to the core accretion scenario, planets form in protostellar disks through the condensation of dust, coagulation of planetesimals, and emergence of protoplanetary embryos. At a few AU in a minimum mass nebula, embryos' growth is quenched by dynamical isolation due to the depletion of planetesimals in their feeding zone. However, embryos with masses (M{sub p} ) in the range of a few Earth masses (M {sub ⊕}) migrate toward a transition radius between the inner viscously heated and outer irradiated regions of their natal disk. Their limiting isolation mass increases with the planetesimals surface density. When M{sub p} > 10 M {sub ⊕}, embryos efficiently accrete gas and evolve into cores of gas giants. We use a numerical simulation to show that despite stream line interference, convergent embryos essentially retain the strength of non-interacting embryos' Lindblad and corotation torques by their natal disks. In disks with modest surface density (or equivalently accretion rates), embryos capture each other in their mutual mean motion resonances and form a convoy of super-Earths. In more massive disks, they could overcome these resonant barriers to undergo repeated close encounters, including cohesive collisions that enable the formation of massive cores.

The Moravian Gate as route of migration of thermophilous bee species to Poland: fact or myth? A case study in the “Góra Gipsowa” steppe reserve and other habitats near Kietrz

Directory of Open Access Journals (Sweden)

Banaszak Józef

2017-06-01

Full Text Available This study complements earlier research on wild bees (Apiformes in the “Góra Gipsowa” steppe reserve and other habitats near the town of Kietrz (SW Poland, close to the Czech border. It also attempts to reassess the opinion of some researchers about the Moravian Gate as a migration route of southern species to Poland. 109 bee species were recorded at the study sites, including 10 red-listed ones; southern species accounted for 16.5% of this number. The hypothetical route of migration of thermophilous bees through the Moravian Gate to Poland was analysed and the species composition of southern species at either side of the Moravian Gate compared. The results of this study indicate that at present the Moravian Gate plays no part in the migration of southern bee species to Poland.

Detours in long-distance migration across the Qinghai-Tibetan Plateau: individual consistency and habitat associations.

Science.gov (United States)

Liu, Dongping; Zhang, Guogang; Jiang, Hongxing; Lu, Jun

2018-01-01

Migratory birds often follow detours when confronted with ecological barriers, and understanding the extent and the underlying drivers of such detours can provide important insights into the associated cost to the annual energy budget and the migration strategies. The Qinghai-Tibetan Plateau is the most daunting geographical barrier for migratory birds because the partial pressure of oxygen is dramatically reduced and flight costs greatly increase. We analyzed the repeated migration detours and habitat associations of four Pallas's Gulls Larus ichthyaetus across the Qinghai-Tibetan Plateau over 22 migration seasons. Gulls exhibited notable detours, with the maximum distance being more than double that of the expected shortest route, that extended rather than reduced the passage across the plateau. The extent of longitudinal detours significantly increased with latitude, and detours were longer in autumn than in spring. Compared with the expected shortest routes, proximity to water bodies increased along autumn migration routes, but detour-habitat associations were weak along spring migration routes. Thus, habitat availability was likely one, but not the only, factor shaping the extent of detours, and migration routes were determined by different mechanisms between seasons. Significant between-individual variation but high individual consistency in migration timing and routes were revealed in both seasons, indicating a stronger influence of endogenous schedules than local environmental conditions. Gulls may benefit from repeated use of familiar routes and stopover sites, which may be particularly significant in the challenging environment of the Qinghai-Tibetan Plateau.

Whirlpool routing for mobility

KAUST Repository

Lee, Jung Woo

2010-01-01

We present the Whirlpool Routing Protocol (WARP), which efficiently routes data to a node moving within a static mesh. The key insight in WARP\\'s design is that data traffic can use an existing routing gradient to efficiently probe the topology, repair the routing gradient, and communicate these repairs to nearby nodes. Using simulation, controlled testbeds, and real mobility experiments, we find that using the data plane for topology maintenance is highly effective due to the incremental nature of mobility updates. WARP leverages the fact that converging flows at a destination make the destination have the region of highest traffic. We provide a theoretical basis for WARP\\'s behavior, defining an "update area" in which the topology must adjust when a destination moves. As long as packets arrive at a destination before it moves outside of the update area, WARP can repair the topology using the data plane. Compared to existing protocols, such as DYMO and HYPER, WARP\\'s packet drop rate is up to 90% lower while sending up to 90% fewer packets.

Petroleum migration pathways and charge concentration: A three-dimensional model

Energy Technology Data Exchange (ETDEWEB)

Hindle, A.D. [Anadarko Algeria Corp., Middlesex (United Kingdom)

1997-09-01

Petroleum migration pathways through a basin are determined by the three-dimensional distribution of discontinuous sealing surfaces, which are usually parallel to bedding. The petroleum migrates below the sealing surface, taking the structurally most advantageous route. The three-dimensional distribution of migration pathways within the petroleum system can be modeled on a personal computer using a program based on the parameters discussed in this paper. Application of the model to the Paris and Williston basins demonstrates that a good correlation between predicted pathways and discovered accumulations can be made using simple models. Pathways form a dense network overlying generating areas in the central parts of basins. Toward the basin margins these routes commonly become increasingly focused into discrete pathways by the sealing-surface morphologies. Eventually, these pathways may reach the surface as seepages. It is important to integrate surface outcrops of migration routes (surface seepages) into migration modeling. Deflection of the pathways from the structurally most advantageous route below the sealing surface may be caused by lateral sealing barriers due to faces variation in the carrier rock below the seal, fault juxtaposition, or cross-formational seals such as salt intrusions. Deflection of pathways also occurs where there are hydrodynamic conditions in response to topography-driven groundwater flow. Zones of vertical migration are associated with facies changes along the horizon of the sealing surface into a nonsealing facies, or juxtaposition to nonsealing strata by faults. Vertical migration from either normally or abnormally pressured strata is most likely to occur into normally or lesser pressured strata at intrabasinal highs where hydrocarbons can be stored and transferred at times of temporary seal rupture.

KNOWLEDGE-BASED MIGRATION AND MOBILITY: THE ECONOMIC 'GAMBLE' OF THE EASTERN NEIGHBOURHOOD

Directory of Open Access Journals (Sweden)

G. Kharlamova

2016-10-01

Full Text Available To what extent can the scientific migration and mobility, and remittances impact the economic development of the donor and recipient states? How significant are they as a resource for the enhancement of the Eastern Partnership? The policy brief provides the results of the quantitative assessment of the costs and benefits of "smart" labour migration in the Eastern Partnership (EaP countries and proposes some policy recommendations to enhance the benefits stemming from knowledge-based migration and mobility flows. We received the proof of mutual causality between human development indicator of donor-state and most significant performance indicators of EaP migration in the EU ("smart mobility". This means that HDI of a donor-state is flexible to the internal situation in the country, and so the positive effect of smart mobility and remittance inflows can be easily absorbed inside the EaP. The same we observed for gross national income of EaP donor-states. However, our approach does not provide the answer: what is exactly the effect or the result. The convergence effect of scientific migration in the EU and the Eastern Partnership region is considered on the ground of the calculative assessment. We considered "fi-convergence" approach, stating that it occurs when the EaP mobility rate grows faster than the EU ones. As for o-convergence, we defined it as a reduction of future rates of variation (inequality, differentiation in the levels of migration of regions (countries. We can conclude that there is the convergence between the EU & EaP in the scientific migration in the years of the EaP initiation, but no results in the process of its fulfilment.

Understanding soaring bird migration through interactions and decisions at the individual level

NARCIS (Netherlands)

van Loon, E.E.; Shamoun-Baranes, J.; Bouten, W.; Davis, S.L.

2011-01-01

Many soaring bird species migrate southwards in autumn from their breeding grounds in Europe and Central Asia towards their wintering grounds. Our knowledge about interactions between migrating birds, thermal selection during migration and mechanisms that lead to flocking or convergent travel

Route Flap Damping Made Usable

Science.gov (United States)

Pelsser, Cristel; Maennel, Olaf; Mohapatra, Pradosh; Bush, Randy; Patel, Keyur

The Border Gateway Protocol (BGP), the de facto inter-domain routing protocol of the Internet, is known to be noisy. The protocol has two main mechanisms to ameliorate this, MinRouteAdvertisementInterval (MRAI), and Route Flap Damping (RFD). MRAI deals with very short bursts on the order of a few to 30 seconds. RFD deals with longer bursts, minutes to hours. Unfortunately, RFD was found to severely penalize sites for being well-connected because topological richness amplifies the number of update messages exchanged. So most operators have disabled it. Through measurement, this paper explores the avenue of absolutely minimal change to code, and shows that a few RFD algorithmic constants and limits can be trivially modified, with the result being damping a non-trivial amount of long term churn without penalizing well-behaved prefixes' normal convergence process.

MIGRATION PATTERNS, USE OF STOPOVER AREAS, AND AUSTRAL SUMMER MOVEMENTS OF SWAINSON'S HAWKS.

Science.gov (United States)

Kochert, Michael N; Fuller, Mark R; Schueck, Linda S; Bond, Laura; Bechard, Marc J; Woodbridge, Brian; Holroyd, Geoff; Martell, Mark; Banasch, Ursula

From 1995-1998, we tracked movements of adult Swainson's Hawks ( Buteo swainsoni ) using satellite telemetry to characterize migration, important stopover areas, and austral summer movements. We tagged 46 hawks from July - September on their nesting grounds in seven U.S. states and two Canadian provinces. Swainson's Hawks basically followed three routes south on a broad front, converged along the east coast of central Mexico, and followed a concentrated corridor to a communal austral summer area in central Argentina. North of 20° N, southward and northward tracks differed little for individuals from east of the Continental Divide but differed greatly (up to 1700 km) for individuals from west of the Continental Divide. Hawks left the breeding grounds mid-August to mid-October; departure dates did not differ by location, year, or sex. South migration lasted 42 to 98 days, and north migration took 51 to 82 days. On south migration, 36% of the Swainson's Hawks departed the nesting grounds nearly 3 weeks earlier than the other radio marked hawks and made stopovers 9.0 - 26.0 days long in seven separate areas, mainly in the southern Great Plains, southern Arizona and New Mexico, and north-central Mexico. The austral period lasted 76 to 128 days. All Swainson's Hawks used a core area in central Argentina within 23% of the 738800 km 2 austral summer range where they frequently moved long distances (up to 1600 km). Conservation of Swainson's Hawks must be an international effort that considers habitats used during nesting and non-nesting seasons including migration stopovers.

Migration patterns and movements of sandhill cranes wintering in central and southwestern Louisiana

Science.gov (United States)

King, Sammy L.; Pierce, Aaron R.; Hersey, Kent R.; Winstead, Nicholas; Hartup, Barry K.

2010-01-01

In this study we trapped wintering sandhill cranes (Grus canadensis) in Louisiana and fitted them with satellite transmitters to determine their migration routes. Four of the 6 sandhill cranes with validated locations and a terminus point used the Central Flyway for spring migration; 2 of these 4 (the only 2 for which we have data) also used the Central Flyway for fall migration. Two of the 6 birds used the Mississippi Flyway for spring migration. The results of this study suggest that reintroduced whooping cranes (G. americana) that intermix and migrate with sandhill cranes that winter in Louisiana may enter the Central Flyway. In addition, the Mississippi Flyway is a viable option to use as a migration route for whooping cranes if they are reintroduced in Louisiana.

Flexible navigation response in common cuckoos Cuculus canorus displaced experimentally during migration

DEFF Research Database (Denmark)

Willemoes, Mikkel; Blas, Julio; Wikelski, Martin

2015-01-01

Migrating birds follow innate species-specific migration programs capable of guiding them along complex spatio-temporal routes, which may include several separate staging areas. Indeed, migration routes of common cuckoos Cuculus canorus show little variation between individuals; yet, satellite...... tracks of 11 experimentally displaced adults revealed an unexpected flexibility in individual navigation responses. The birds compensated for the translocation to unfamiliar areas by travelling toward population-specific staging areas, demonstrating true navigation capabilities. Individual responses...

Channels to West: Exploring the Migration Routes between Romania and France

Directory of Open Access Journals (Sweden)

Marius Lupșa Matichescu

2017-10-01

Full Text Available The integration of East European Countries in European Union has long-term consequences, with migration being one of the main social effects of this process. From an economic perspective, the research on migration has attracted considerable attention, whereas the analyses focused on the social networks are more scarce. The importance of these social networks becomes more substantial due to their quality and ability to reduce costs, risks of movement and uncertainty. Although the migratory networks are known at national levels, there are very few data related to the territorial distribution of migration network between origin and destination areas. In this context, Romania registered the highest level of emigration toward Western European countries, and this case study offers illustrative insights for the broader literature. In order to illustrate the territorial distribution of migrants’ network between Romania and France, we used an exhaustive analysis of the trajectories of all clients who used one of the largest transport companies operating between Romania and France (8094 cases. Using the benefits of this evidence-based approach, we identified the regions and the Romanian towns most affected by the migration phenomenon. Complementary, we illustrated the territorial distribution and the preferred destination regions in France for the Romanian immigrants. We present the migration networks that exist between the towns of the two countries and identify the intensity of each migration circuit.

Narrow-front loop migration in a population of the common cuckoo Cuculus canorus, as revealed by satellite telemetry.

Directory of Open Access Journals (Sweden)

Mikkel Willemoes

Full Text Available Narrow migration corridors known in diurnal, social migrants such as raptors, storks and geese are thought to be caused by topographical leading line effects in combination with learning detailed routes across generations. Here, we document narrow-front migration in a nocturnal, solitary migrant, the common cuckoo Cuculus canorus, using satellite telemetry. We tracked the migration of adult cuckoos from the breeding grounds in southern Scandinavia (n = 8, to wintering sites in south-western Central Africa (n = 6 and back to the breeding grounds (n = 3. Migration patterns were very complex; in addition to the breeding and wintering sites, six different stopover sites were identified during the 16,000 km annual route that formed a large-scale clockwise loop. Despite this complexity, individuals showed surprisingly similar migration patterns, with very little variation between routes. We compared observed tracks with simulated routes based on vector orientation (with and without effects of barriers on orientation and survival. Observed distances between routes were often significantly smaller than expected if the routes were established on the basis of an innate vector orientation programme. Average distance between individuals in eastern Sahel after having migrated more than 5,000 km for example, was merely 164 km. This implies that more sophisticated inherent guiding mechanisms, possibly involving elements of intermediate goal area navigation or more elaborate external cues, are necessary to explain the complex narrow-front migration pattern observed for the cuckoos in this study.

Motorized Migrations: the Future or Mere Fantasy?

Science.gov (United States)

Ellis, D.H.; Sladen, William J. L.; Lishman, W.A.; Clegg, K.R.; Duff, J.W.; Gee, G.F.; Lewis, J.C.

2003-01-01

In 15 experiments from 1993-2002, we led cranes, geese, or swans on their first southward migration with either ultralight aircraft or vehicles on the ground. These experiments reveal that large birds can be readily trained to follow and most will return north (and south) in subsequent migrations unassisted. These techniques can now be used to teach birds new (or forgotten) migration paths. Although we are constantly improving our training techniques, we now have an operational program that can be broadly applied to those species where juveniles learn migration routes from their parents.

Tracking from the tropics reveals behaviour of juvenile songbirds on their first spring migration.

Directory of Open Access Journals (Sweden)

Emily A McKinnon

Full Text Available Juvenile songbirds on spring migration travel from tropical wintering sites to temperate breeding destinations thousands of kilometres away with no prior experience to guide them. We provide a first glimpse at the migration timing, routes, and stopover behaviour of juvenile wood thrushes (Hylocichla mustelina on their inaugural spring migration by using miniaturized archival geolocators to track them from Central America to the U.S. and Canada. We found significant differences between the timing of juvenile migration and that of more experienced adults: juveniles not only departed later from tropical wintering sites relative to adults, they also became progressively later as they moved northward. The increasing delay was driven by more frequent short stops by juveniles along their migration route, particularly in the U.S. as they got closer to breeding sites. Surprisingly, juveniles were just as likely as adults to cross the Gulf of Mexico, an open-water crossing of 800-1000 km, and migration route at the Gulf was not significantly different for juveniles relative to adults. To determine if the later departure of juveniles was related to poor body condition in winter relative to adults, we examined percent lean body mass, fat scores, and pectoral muscle scores of juvenile versus adult birds at a wintering site in Belize. We found no age-related differences in body condition. Later migration timing of juveniles relative to adults could be an adaptive strategy (as opposed to condition-dependent to avoid the high costs of fast migration and competition for breeding territories with experienced and larger adults. We did find significant differences in wing size between adults and juveniles, which could contribute to lower flight efficiency of juveniles and thus slower overall migration speed. We provide the first step toward understanding the "black box" of juvenile songbird migration by documenting their migration timing and en route performance.

Routing Optimization of Intelligent Vehicle in Automated Warehouse

Directory of Open Access Journals (Sweden)

Yan-cong Zhou

2014-01-01

Full Text Available Routing optimization is a key technology in the intelligent warehouse logistics. In order to get an optimal route for warehouse intelligent vehicle, routing optimization in complex global dynamic environment is studied. A new evolutionary ant colony algorithm based on RFID and knowledge-refinement is proposed. The new algorithm gets environmental information timely through the RFID technology and updates the environment map at the same time. It adopts elite ant kept, fallback, and pheromones limitation adjustment strategy. The current optimal route in population space is optimized based on experiential knowledge. The experimental results show that the new algorithm has higher convergence speed and can jump out the U-type or V-type obstacle traps easily. It can also find the global optimal route or approximate optimal one with higher probability in the complex dynamic environment. The new algorithm is proved feasible and effective by simulation results.

Roosts and migrations of swallows

OpenAIRE

Winkler, David W.

2006-01-01

Swallows of the north temperate zone display a wide variety of territorial behaviour during the breeding season, but as soon as breeding is over, they all appear to adopt a pattern of independent diurnal foraging interleaved with aggregation every night in dense roosts. Swallows generally migrate during the day, feeding on the wing. On many stretches of their annual journeys, their migrations can thus be seen as the simple spatial translation of nocturnal roost sites with foraging routes stra...

Fish ladder of Lajeado Dam: migrations on one-way routes?

Directory of Open Access Journals (Sweden)

Angelo Antônio Agostinho

Full Text Available Fish ladders are generally conceived to reestablish connectivity among critical habitats for migratory species, thus mitigating the impacts of the blockage of migration routes by dams. If this management tool is to be meaningful for conserving fish species, it must provide a fully permeable connection and assure both upward and downward movements. However, because reservoirs have very different hydrodynamics than the original river, it is expected that, at least in the inner area, they may constitute an additional barrier to this movement, especially for descending fish. Thus, the present study sought to determine if migratory fish and their offspring disperse downstream from the dam after ascending a ladder and spawning in the upper reaches of a basin. To achieve this purpose, we evaluated the limitation imposed by lentic areas to the descent of eggs, larvae and adults of migratory species; we also determined the abundance and composition of larvae present in the plankton near the dam, and compared the intensity of the upward and downward movements of adult fish. Samples of ichthyoplankton were taken upriver, inside the reservoir, in the river downstream from the dam, and in the forebay of the Lajeado Dam on the Tocantins River (Luis Eduardo Magalhães Hydroelectric Plant, from October, 1999 through September, 2004. The densities of fish ascending and descending the ladder were determined experimentally on eight occasions, from June, 2004 to March, 2005. Due to difficulties in identifying the true fish origin (up or down in the environments connected by the fish passage system, the evaluation of the distribution of migratory fish in reservoirs was based on the landings of the commercial fishery conducted along the Itaipu Reservoir during the four years preceding (2001 through 2003 the construction of the lateral channel (fish-passage mechanism. Fish eggs and larvae drifting down the Tocantins River did not appear in samples taken in the lower

Dispersal and migration

Directory of Open Access Journals (Sweden)

Schwarz, C.

2004-06-01

overlay maps of effort to try and remove any induced artefacts in the data. Differences in timing or the route of migration has often been studies separately. Lokki and Saurola (Lokki & Saurola, 2004 develop an omnibus procedure to test if the migration timing and/or route differ among two populations of birds (e.g. males vs females. It uses a randomization test to calibrate the test statistic. However, it makes the key assumptions about equal recovery effort in time and space so that the method may be most applicable to comparison among species with similar migration timing and movement to keep differential sighting/recovery rates from affecting the result. Of course, it is in these cases where it is most difficulty to separate the groups which will require substantial samples to have good performance. Thorup and Rahbek (Thorup & Rahbek, 2004 provide a framework for accounting for unequal spatial recovery probability investigating the geometric influence of ocean and sea on observed migratory patterns. Taking the data set of Pied Flycatchers (Ficedula hypoleuca ringed as nestlings in Scandinavia and recovered en route on their initial migration and using a model based on the clock–and–compass innate navigation hypothesis they are showing that geometric constraints explain quite a bit of the variation in ring–recoveries. The model also shows that ring recovery patterns do reflect the migratory patterns, and that they are suitable for an analysis of the concentration of the migratory route which is important for the general use of ringing data in studies of migration. This is important for the general use of ringing data in studies of migration and dispersal. The new approach has also implications for understanding the migratory orientation program. The compiled papers highlight some novel ideas of how to analyse band recoveries to investigate migration routes and migration behaviour as well as dispersal patterns among birds and dolphins. Multistate modeling appears

Radionuclide-migration model for buried waste at the Savannah River Plant

International Nuclear Information System (INIS)

King, C.M.; Root, R.W. Jr.

1982-01-01

Solid waste has been buried at the Savannah River Plant burial ground since 1953. The solid waste is contaminated with alpha-emitting transuranium (TRU) nuclides, with beta-gamma-emitting activation and fission products, and with tritium. To provide guidance for the current use and eventual permanent retirement of the burial site from active service, a radionuclide environmental transport model has been used to project the potential influence on man if the burial site were occupied after decommissioning. The model used to simulate nuclide migration includes the various hydrological, animal, vegetative, atmospheric, and terrestrial pathways in estimating dose to man as a function of time. Specific scenarios include a four-person home farm on the 195-acre burial ground. Key input to the model includes site-specific nuclide migration rates through soil, nuclide distribution coefficients, and site topography. Coupled with literature data on plant and animal concentration factors, transfer coefficients reflecting migration routes are input to a set of linear differential equations for subsequent matrix solution. Output from the model is the nuclide-specific decayed curie intake by man. To discern principal migration routes, model-compartment inventories with time can also be displayed. Dose projections subsequently account for organ concentrations in man for the nuclide of interest. Radionuclide migration has been examined in depth with the dose-to-man model. Movement by vegetative pathways is the primary route for potential dose to man for short-lived isotopes. Hydrological routes provide a secondary scheme for long-lived nuclides. Details of model methodology are reviewed

Feminization of Migration Routes and Integration Aspects in Trieste Area and Friuli-Venezia Giulia Region

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Melita Richter Malabotta

2002-12-01

Full Text Available Italian society is going through deep structural demographic and cultural changes whereby its emigration pattern has been reversed to the extent that the country is now experiencing intensive immigration. Pre-supposing the two basic characteristics of the migration routes which have become visible in the last decade – namely feminization and internal diversification of universal migrant, this article has tried to show the market typology (a characteristic not only of Italy but other Mediterranean countries of the EU which contributes to the gender differentiation of the foreigners' work, paying special attention to the position of an immigrant woman in the integration process into the native community. In that context, the analysis is directed towards the Friuli-Venezia Giulia Region and the town of Trieste which have proved themselves to be unique in their acceptance of newcomers, among whom the most numerous being the ex-Yugoslavian (mainly Serbian population. Issues which have been touched include the recent history of dynamic Italian-Yugoslav relationships, the importance of the border, the daily cross-border migration mostly performed by the female workforce and the multiculturalism of Trieste as a border town. The so-called stable migration going through “family unification” has also been observed, a process responsible for the constant rise in the numbers of immigrant women and their underage children. In the way of their harmonic integration into the new society stand numerous obstacles: the language barrier, prejudice, the social invisibility of foreign women, their domestication, professional disqualification and coerced collective identity enforced by national or monoethnic associations. In school – an institution that forms a relationship with the foreign students’ mothers – attempts are being made to break free from this state of social invisibility. Similarly, in multicultural associations and societies, immigrant women

Tracking the Autumn Migration of the Bar-Headed Goose (Anser indicus with Satellite Telemetry and Relationship to Environmental Conditions

Directory of Open Access Journals (Sweden)

Yaonan Zhang

2011-01-01

Full Text Available The autumn migration routes of bar-headed geese captured before the 2008 breeding season at Qinghai Lake, China, were documented using satellite tracking data. To assess how the migration strategies of bar-headed geese are influenced by environmental conditions, the relationship between migratory routes, temperatures, and vegetation coverage at stopovers sites estimated with the Normalized Difference Vegetation Index (NDVI were analyzed. Our results showed that there were four typical migration routes in autumn with variation in timing among individuals in start and end times and in total migration and stopover duration. The observed variation may be related to habitat type and other environmental conditions along the routes. On average, these birds traveled about 1300 to 1500 km, refueled at three to six stopover sites and migrated for 73 to 83 days. The majority of the habitat types at stopover sites were lake, marsh, and shoal wetlands, with use of some mountainous regions, and farmland areas.

Routing protocol extension for resilient GMPLS multi-domain networks

DEFF Research Database (Denmark)

Manolova, Anna Vasileva; Ruepp, Sarah Renée; Romeral, Ricardo

2010-01-01

This paper evaluates the performance of multi-domain networks under the Generalized Multi-Protocol Label Switching control framework in case of a single inter-domain link failure. We propose and evaluate a routing protocol extension for the Border Gateway Protocol, which allows domains to obtain...... two Autonomous System disjoint paths and use them efficiently under failure conditions. Three main applications for the protocol extension are illustrated: reducing traffic loss on existing connections by xploiting pre-selected backup paths derived with our proposal, applying multi-domain restoration...... as survivability mechanism in case of single link failure, and employing proper failure notification mechanisms for routing of future connection requests under routing protocol re-convergence. Via simulations we illustrate the benefits of utilizing the proposed routing protocol extension for networks employing...

Inclusive growth?: Labour migration and poverty in India

OpenAIRE

Haan, Arjan

2011-01-01

textabstractThis paper discusses the relationship between labour migration and poverty in India. This is placed against the on-going debates on changes in patterns of employment and job creation in India, during the periods of economic liberalization, under the Inclusive Growth policies since 2004, and under the impact of the global financial crisis, and growing inequalities. The paper focuses on the migration patterns of deprived social groups, analyse whether migration form a routes out of ...

Fish Species in a Changing World: The Route and Timing of Species Migration between Tropical and Temperate Ecosystems in Eastern Atlantic.

Directory of Open Access Journals (Sweden)

Awaluddin Halirin Kaimuddin

2016-09-01

Full Text Available The presence of tropical species has been reported in Atlantic-European waters with increasing frequency in recent years. Unfortunately, the history of their migrations is not well understood. In this study, we examined the routes and timing of fish migrations in several ecosystems of the East Atlantic Ocean, combining several publicly available and unpublicized datasets on species occurrences. The species studied were those noted as exotic or rare outside their previous known area of distribution. We used sea surface temperature (SST data obtained from 30 years of satellite observation to define three distinct time periods. Within these periods, temperature trends were studied in six ecosystems: the North Sea, the Celtic Sea, the South European Atlantic Waters, the Mediterranean Sea, the Canary Current and the Guinea Current. We also incorporated bathymetry data to describe the distribution of species. Measurement across a relatively large spatial extent was made possible by incorporating the capabilities of GIS.While SST increased consistently over time in all of the ecosystems observed, the change in number of species differed among ecosystems. The number of species in the middle regions, such as the South European Atlantic Shelf and the Western Mediterranean Sea, tended to increase over time. These regions received numbers of species from the lower or the upper latitudes according to season. Of all of the species observed in the recent period, 7 species from the Canary Current tended to be found in the Western Mediterranean Sea, and 6 species from these two regions extended their distributions to the South European Atlantic Shelf. Twelve species from the Canary Current moved seasonally to the Guinea Current. In the northern regions, 13 species moved seasonally in the North Sea and the Celtic Seas, and 12 of these species reached the South European Atlantic Shelf.This study presents a picture of routes and timing of species migration at the

One year of migration data for a western yellow-billed cuckoo

Science.gov (United States)

Sechrist, Juddson D.; Paxton, Eben H.; Ahlers, Darrell D.; Doster, Robert H.; Ryan, Vicky M.

2012-01-01

In 2009, we studied the migration of the Western Yellow-billed Cuckoo by capturing 13 breeding birds on the middle Rio Grande, New Mexico, and attaching a 1.5-g Mk 14-S British Antarctic Survey geolocator to each bird. In 2010, we recaptured one of the cuckoos, enabling us to download its geolocation data. The cuckoo had flown approximately 9500 km during its southward migration, traveling through Central America to winter in portions of Bolivia, Brazil, Paraguay, and Argentina. The spring migration route differed somewhat from the fall route, with the cuckoo bypassing Central America to migrate through the Caribbean. Additionally, it moved between New Mexico and Mexico at the end of summer in 2009 and again in 2010 before being recaptured at its breeding site. Our results, albeit from one individual, hint at a dynamic migration strategy and have broad implications for the ecology and conservation of the Western Yellow-billed Cuckoo, a species of conservation concern.

MIGRATION PATTERNS, USE OF STOPOVER AREAS, AND AUSTRAL SUMMER MOVEMENTS OF SWAINSON’S HAWKS

Science.gov (United States)

Kochert, Michael N.; Fuller, Mark R.; Schueck, Linda S.; Bond, Laura; Bechard, Marc J.; Woodbridge, Brian; Holroyd, Geoff; Martell, Mark; Banasch, Ursula

2015-01-01

From 1995–1998, we tracked movements of adult Swainson’s Hawks (Buteo swainsoni) using satellite telemetry to characterize migration, important stopover areas, and austral summer movements. We tagged 46 hawks from July - September on their nesting grounds in seven U.S. states and two Canadian provinces. Swainson’s Hawks basically followed three routes south on a broad front, converged along the east coast of central Mexico, and followed a concentrated corridor to a communal austral summer area in central Argentina. North of 20° N, southward and northward tracks differed little for individuals from east of the Continental Divide but differed greatly (up to 1700 km) for individuals from west of the Continental Divide. Hawks left the breeding grounds mid-August to mid-October; departure dates did not differ by location, year, or sex. South migration lasted 42 to 98 days, and north migration took 51 to 82 days. On south migration, 36% of the Swainson’s Hawks departed the nesting grounds nearly 3 weeks earlier than the other radio marked hawks and made stopovers 9.0 – 26.0 days long in seven separate areas, mainly in the southern Great Plains, southern Arizona and New Mexico, and north-central Mexico. The austral period lasted 76 to 128 days. All Swainson’s Hawks used a core area in central Argentina within 23% of the 738800 km2 austral summer range where they frequently moved long distances (up to 1600 km). Conservation of Swainson’s Hawks must be an international effort that considers habitats used during nesting and non-nesting seasons including migration stopovers. PMID:26380528

Were rivers flowing across the Sahara during the last interglacial? Implications for human migration through Africa.

Directory of Open Access Journals (Sweden)

Tom J Coulthard

Full Text Available Human migration north through Africa is contentious. This paper uses a novel palaeohydrological and hydraulic modelling approach to test the hypothesis that under wetter climates c.100,000 years ago major river systems ran north across the Sahara to the Mediterranean, creating viable migration routes. We confirm that three of these now buried palaeo river systems could have been active at the key time of human migration across the Sahara. Unexpectedly, it is the most western of these three rivers, the Irharhar river, that represents the most likely route for human migration. The Irharhar river flows directly south to north, uniquely linking the mountain areas experiencing monsoon climates at these times to temperate Mediterranean environments where food and resources would have been abundant. The findings have major implications for our understanding of how humans migrated north through Africa, for the first time providing a quantitative perspective on the probabilities that these routes were viable for human habitation at these times.

Consideration of some difficulties in migration velocity analysis; Migration velocity analysis no shomondai ni kansuru kento

Energy Technology Data Exchange (ETDEWEB)

Akama, K [Japan National Oil Corp., Tokyo (Japan). Technology Research Center; Matsuoka, T [Japan Petroleum Exploration Corp., Tokyo (Japan)

1997-10-22

Concerning migration velocity analysis in the seismic exploration method, two typical techniques, out of velocity analysis techniques using residual moveout in the CIP gather, are verified. Deregowski`s method uses pre-stacking deep-level migration records for velocity analysis to obtain velocities free of spatial inconsistency and not dependent on the velocity structure. This method is very like the conventional DMO velocity analysis method and is easy to understand intuitively. In this method, however, error is apt to be aggravated in the process of obtaining the depth-sector velocity from the time-RMS velocity. Al-Yahya`s method formulates the moveout residual in the CIP gather. This assumes horizontal stratification and a small residual velocity, however, and fails to guarantee convergence in the case of a steep structure or a grave model error. In the updating of the velocity model, in addition, it has to maintain required accuracy and, at the same time, incorporate smoothing to ensure not to deteriorate high convergence. 2 refs., 5 figs.

Diverging patterns with endogenous labor migration.

Science.gov (United States)

Reichlin, P; Rustichini, A

1998-05-05

"The standard neoclassical model cannot explain persistent migration flows and lack of cross-country convergence when capital and labor are mobile. Here we present a model where both phenomena may take place.... Our model is based on the Arrow-Romer approach to endogenous growth theory. We single out the importance of a (however weak) scale effect from the size of the workforce.... The main conclusion of this simple model is that lack of convergence, or even divergence, among countries is possible, even with perfect capital mobility and labor mobility." excerpt

Plane-wave Least-squares Reverse Time Migration

KAUST Repository

Dai, Wei

2012-11-04

Least-squares reverse time migration is formulated with a new parameterization, where the migration image of each shot is updated separately and a prestack image is produced with common image gathers. The advantage is that it can offer stable convergence for least-squares migration even when the migration velocity is not completely accurate. To significantly reduce computation cost, linear phase shift encoding is applied to hundreds of shot gathers to produce dozens of planes waves. A regularization term which penalizes the image difference between nearby angles are used to keep the prestack image consistent through all the angles. Numerical tests on a marine dataset is performed to illustrate the advantages of least-squares reverse time migration in the plane-wave domain. Through iterations of least-squares migration, the migration artifacts are reduced and the image resolution is improved. Empirical results suggest that the LSRTM in plane wave domain is an efficient method to improve the image quality and produce common image gathers.

Plane-wave least-squares reverse-time migration

KAUST Repository

Dai, Wei; Schuster, Gerard T.

2013-01-01

. The merits of plane-wave prestack LSRTM are the following: (1) plane-wave prestack LSRTM can sometimes offer stable convergence even when the migration velocity has bulk errors of up to 5%; (2) to significantly reduce computation cost, linear phase

Privacy-Preserving Interdomain Routing at Internet Scale

Directory of Open Access Journals (Sweden)

Asharov Gilad

2017-07-01

Full Text Available The Border Gateway Protocol (BGP computes routes between the organizational networks that make up today’s Internet. Unfortunately, BGP suffers from deficiencies, including slow convergence, security problems, a lack of innovation, and the leakage of sensitive information about domains’ routing preferences. To overcome some of these problems, we revisit the idea of centralizing and using secure multi-party computation (MPC for interdomain routing which was proposed by Gupta et al. (ACM HotNets’12. We implement two algorithms for interdomain routing with state-of-the-art MPC protocols. On an empirically derived dataset that approximates the topology of today’s Internet (55 809 nodes, our protocols take as little as 6 s of topology-independent precomputation and only 3 s of online time. We show, moreover, that when our MPC approach is applied at country/region-level scale, runtimes can be as low as 0.17 s online time and 0.20 s pre-computation time. Our results motivate the MPC approach for interdomain routing and furthermore demonstrate that current MPC techniques are capable of efficiently tackling real-world problems at a large scale.

Migration routes and staging areas of Abdim's Storks Ciconia ...

African Journals Online (AJOL)

This paper presents the results of a satellite tracking study of seven adult Abdim's Storks Ciconia abdimii that were followed from the nesting areas in southern Niger across the equator to the non-breeding range and back. Post-breeding migration started between early November and early December when all birds ...

Migrations to Ankara by Railway and Settlement Policy (1890-1910

Directory of Open Access Journals (Sweden)

İhsan Seddar Kaynar

2016-06-01

Full Text Available The Anatolian Railway began running between Ankara and Haydarpaşa in Istanbul via İzmit and Eskişehir in early 1893, making transportation from Istanbul to the interior of Anatolia very easy. In late 1892, before the railroad was opened, policymakers prepared official reports on the resettlement of migrants along the rail route from Eskişehir to Ankara; and made regulations accordingly. This studyexamines the route of this migration, which first run to the port of İzmit by sea and then reached Ankara by rail. This article discusses the politics of resettlement and the conditions of migrants settled on the railway route during the twenty-year period between 1890 and 1910, when the Balkan Wars provoked mass migration to Anatolia from the Balkans. It analyzes the locations of the new settlements, the conditions in newly founded villages, and the habitability of the wasteland along the railway route. Daily rations, state aid for housing, types of production, agricultural styles, and the position of artisans will also be considered.

Direct observations of American eels migrating across the continental shelf to the Sargasso Sea.

Science.gov (United States)

Béguer-Pon, Mélanie; Castonguay, Martin; Shan, Shiliang; Benchetrit, José; Dodson, Julian J

2015-10-27

Since inferring spawning areas from larval distributions in the Sargasso Sea a century ago, the oceanic migration of adult American eels has remained a mystery. No adult eel has ever been observed migrating in the open ocean or in the spawning area. Here, we track movements of maturing eels equipped with pop-up satellite archival tags from the Scotian Shelf (Canada) into the open ocean, with one individual migrating 2,400 km to the northern limit of the spawning site in the Sargasso Sea. The reconstructed routes suggest a migration in two phases: one over the continental shelf and along its edge in shallow waters; the second in deeper waters straight south towards the spawning area. This study is the first direct evidence of adult Anguilla migrating to the Sargasso Sea and represents an important step forward in the understanding of routes and migratory cues.

ASSESSMENT OF RIP-V1 AND OSPF-V2 PROTOCOL WITH CONSIDERATION OF CONVERGENCE CRITERIA AND SENDING PROTOCOLS TRAFFIC

Directory of Open Access Journals (Sweden)

Hamed Jelodar

2014-03-01

Full Text Available Routing Protocols are underlying principles in networks like internet, transport and mobile. Routing Protocols include a series of rules and algorithms that consider routing metric and select the best way for sending healthy data packets from origin to destination. Dynamic routing protocol compatible to topology has a changeable state. RIP and OSPF are dynamic routing protocol that we consider criteria like convergence and sending protocols traffic assessment RIP first version and OSPF second version. By the test we have done on OPNET stimulation we understood that the OSPF protocol was more efficient than RIP protocol.

Age ratios and their possible use in determining autumn routes of passerine migrants

Science.gov (United States)

C. John Ralph

1981-01-01

Age ratios and abundance of 61 migrant passerine species comprising more than 42,000 birds were analyzed in an attempt to determine patterns of migration. The data were collected at 10 stations from coastal Massachusetts to inland Pennsylvania. Age ratios are thought to be useful in determining routes of migration. The principal criteria for the edge of a species...

Routes of human trafficking in Europe and the position of Serbia on them

Directory of Open Access Journals (Sweden)

Ćopić Sanja

2008-01-01

Full Text Available Human trafficking as a form of organized crime is showing its increase today, changing at the same time its structure and characteristics. Some factors that contribute to such a situation are global trends that result in huge social and economic inequalities in the world, but also turbulences and problems that are affecting certain regions (wars, political instability, ethnic conflicts, militarization etc.. Human trafficking, as a complex social phenomenon that encompasses different forms of acting, subjects and aims, can be analyzed within different concepts. One of them refers to the issue of broader migration flows and migration control policy. Namely, from the global perspective, trafficking in human beings can be mostly considered as a form of 'organized illegal migration'. Due to that, it seems important to consider the issue of routes through which this form of migration is realized today. Discovering human trafficking routes, as well as other forms of illegal movement of people and illegal forms of trade are very important from the point of view of implementing adequate measures and relocation of resources in order to suppress these forms of socially unacceptable phenomena. Creating adequate anti-trafficking activities is important on national, regional and international levels. Keeping that in mind, the aim of this paper is to look into the contemporary routes of human trafficking within Europe and find out what is the position of Serbia on these routes, as well to examine possible changes that happened in this field during past several years. This will be done on the basis of the analysis of relevant literature, as well as on some preliminary findings of the survey on male victims of human trafficking in Serbia, which is currently conducted by the Victimology Society of Serbia.

Analysis of energy efficient routing protocols for implementation of a ubiquitous health system

Science.gov (United States)

Kwon, Jongwon; Park, Yongman; Koo, Sangjun; Ayurzana, Odgeral; Kim, Hiesik

2007-12-01

The innovative Ubiquitous-Health was born through convergence of medical service, with development of up to date information technologies and ubiquitous IT. The U-Health can be applied to a variety of special situations for managing functions of each medical center efficiently. This paper focuses on estimation of various routing protocols for implementation of U-health monitoring system. In order to facilitate wireless communication over the network, a routing protocol on the network layer is used to establish precise and efficient route between sensor nodes so that information acquired from sensors may be delivered in a timely manner. A route establishment should be considered to minimize overhead, data loss and power consumption because wireless networks for U-health are organized by a large number of sensor nodes which are small in size and have limited processing power, memory and battery life. In this paper a overview of wireless sensor network technologies commonly known is described as well as evaluation of three multi hop routing protocols which are flooding, gossiping and modified low energy adaptive clustering hierarchy(LEACH) for use with these networks using TOSSIM simulator. As a result of evaluation the integrated wireless sensor board was developed in particular. The board is embedded device based on AVR128 porting TinyOS. Also it employs bio sensor measures blood pressure, pulse frequency and ZigBee module for wireless communication. This paper accelerates the digital convergence age through continual research and development of technologies related the U-Health.

Out of Africa: the importance of rivers as human migration corridors

Science.gov (United States)

Ramirez, J. A.; Coulthard, T. J.; Rogerson, M.; Barton, N.; Bruecher, T.

2013-12-01

The route and timing of Homo sapiens exiting Africa remains uncertain. Corridors leading out of Africa through the Sahara, the Nile Valley, and the Red Sea coast have been proposed as migration routes for anatomically modern humans 80,000-130,000 years ago. During this time climate conditions in the Sahara were wetter than present day, and monsoon rainfall fed rivers that flowed across the desert landscape. The location and timing of these rivers may have supported human migration northward from central Africa to the Mediterranean coast, and onwards to Europe or Asia. Here, we use palaeoclimate rainfall and a hydrological model to spatially simulate and quantitatively test the existence of three major rivers crossing the Sahara from south to north during the time of human migration. We provide evidence that, given realistic underlying climatology, the well-known Sahabi and Kufrah rivers very likely flowed across modern day Libya and reached the coast. More unexpectedly an additional river crossed the core of the Sahara through Algeria (Irharhar river) and flowed into the Chotts basin. The Irharhar river is unique, because it links locations in central Africa experiencing monsoon climates with temperate coastal Mediterranean environments where food and resources were likely abundant. From an ecological perspective, this little-known corridor may prove to be the most parsimonious migration route. Support for the Irharar as a viable migration corridor is provided by its geographic proximity to middle Stone Age archaeological artefacts found in North Africa. Our new, highly novel approach provides the first quantitative analysis of the likelihood that rivers occurred during the critical period of human migration out of Africa. Simulated probability of surface water in North Africa during the last interglacial and the location of tools and ornaments from the Middle Stone Age.

Do convergent developmental mechanisms underlie convergent phenotypes?

Science.gov (United States)

Wray, Gregory A.

2002-01-01

Convergence is a pervasive evolutionary process, affecting many aspects of phenotype and even genotype. Relatively little is known about convergence in developmental processes, however, nor about the degree to which convergence in development underlies convergence in anatomy. A switch in the ecology of sea urchins from feeding to nonfeeding larvae illustrates how convergence in development can be associated with convergence in anatomy. Comparisons to more distantly related taxa, however, suggest that this association may be limited to relatively close phylogenetic comparisons. Similarities in gene expression during development provide another window into the association between convergence in developmental processes and convergence in anatomy. Several well-studied transcription factors exhibit likely cases of convergent gene expression in distantly related animal phyla. Convergence in regulatory gene expression domains is probably more common than generally acknowledged, and can arise for several different reasons. Copyright 2002 S. Karger AG, Basel.

Indonesia's migration transition.

Science.gov (United States)

Hugo, G

1995-01-01

This article describes population movements in Indonesia in the context of rapid and marked social and economic change. Foreign investment in Indonesia is increasing, and global mass media is available to many households. Agriculture is being commercialized, and structural shifts are occurring in the economy. Educational levels are increasing, and women's role and status are shifting. Population migration has increased over the decades, both short and long distance, permanent and temporary, legal and illegal, and migration to and between urban areas. This article focuses specifically on rural-to-urban migration and international migration. Population settlements are dense in the agriculturally rich inner areas of Java, Bali, and Madura. Although the rate of growth of the gross domestic product was 6.8% annually during 1969-94, the World Bank ranked Indonesia as a low-income economy in 1992 because of the large population size. Income per capita is US $670. Indonesia is becoming a large exporter of labor to the Middle East, particularly women. The predominance of women as overseas contract workers is changing women's role and status in the family and is controversial due to the cases of mistreatment. Malaysia's high economic growth rate of over 8% per year means an additional 1.3 million foreign workers and technicians are needed. During the 1980s urban growth increased at a very rapid rate. Urban growth tended to occur along corridors and major transportation routes around urban areas. It is posited that most of the urban growth is due to rural-to-urban migration. Data limitations prevent an exact determination of the extent of rural-to-urban migration. More women are estimated to be involved in movements to cities during the 1980s compared to the 1970s. Recruiters and middlemen have played an important role in rural-to-urban migration and international migration.

Trends in population growth in China's towns during the eighties, and town population in-migration and its decisive factors: a historic convergence of two types of demographic change.

Science.gov (United States)

Wei, J

1990-01-01

Relying on socioeconomic and population statistics, as well as population censuses, the author examines the growth of China's towns in the 1980s due to in-migration, and considers the economic causes and impact of the growth of towns. Prior to 1984, China's urbanization had been slow and uneven. But in the 4 years from 1984-87, China's urban population grew 3.8 times faster than the period before 1984. and unlike the previous pattern of urbanization, slightly over half of the urban growth occurred in small cities and towns. The rapid growth of towns was due to an unprecedented level of in-migration into towns from agricultural villages. This population transformed itself into a nonagricultural population. The author attributes the increase in urbanization and its changing patterns to a historic convergence: the shift in industry for the agricultural population and a regional shift for the village population--realized through a form of village-to-town population migration. The author goes on to examine the development of small-town enterprises, facilitated after the rural reform of 1984. The author notes that since that year, small-town industries have flourished, a development that has had a number of beneficial effects on both the provincial areas and the nation as a whole. Finally, the author considers the factors that have fueled town population in-migration: 1) in most provinces, higher incomes in towns have attracted people from the villages; and 2) in provinces with little discrepancy in income between town and village, a combination of the regions' relative isolation and government policy preventing migration to cities have spurred the growth of towns.

Satellite tracking of two Montagu's Harriers (Circus pygargus) : Dual pathways during autumn migration

NARCIS (Netherlands)

Trierweiler, Christiane; Koks, Ben J.; Drent, Rudi H.; Exo, Klaus-Michael; Komdeur, Jan; Dijkstra, Cor; Bairlein, Franz

2007-01-01

Autumn migration routes of two Dutch female Montagu's Harriers (Circus pygargus) were documented for the first time using satellite telemetry. Both migrated to their African wintering area-one via the Straits of Gibraltar through the Mediterranean and the other via Italy/Tunisia. The rate of travel

Q-Least Squares Reverse Time Migration with Viscoacoustic Deblurring Filters

KAUST Repository

Chen, Yuqing; Dutta, Gaurav; Dai, Wei; Schuster, Gerard T.

2017-01-01

Viscoacoustic least-squares reverse time migration (Q-LSRTM) linearly inverts for the subsurface reflectivity model from lossy data. Compared to the conventional migration methods, it can compensate for the amplitude loss in the migrated images because of the strong subsurface attenuation and can produce reflectors that are accurately positioned in depth. However, the adjoint Q propagators used for backward propagating the residual data are also attenuative. Thus, the inverted images from Q-LSRTM are often observed to have lower resolution when compared to the benchmark acoustic LSRTM images from acoustic data. To increase the resolution and accelerate the convergence of Q-LSRTM, we propose using viscoacoustic deblurring filters as a preconditioner for Q-LSRTM. These filters can be estimated by matching a simulated migration image to its reference reflectivity model. Numerical tests on synthetic and field data demonstrate that Q-LSRTM combined with viscoacoustic deblurring filters can produce images with higher resolution and more balanced amplitudes than images from acoustic RTM, acoustic LSRTM and Q-LSRTM when there is strong attenuation in the background medium. The proposed preconditioning method is also shown to improve the convergence rate of Q-LSRTM by more than 30 percent in some cases and significantly compensate for the lossy artifacts in RTM images.

Q-Least Squares Reverse Time Migration with Viscoacoustic Deblurring Filters

KAUST Repository

Chen, Yuqing

2017-08-02

Viscoacoustic least-squares reverse time migration (Q-LSRTM) linearly inverts for the subsurface reflectivity model from lossy data. Compared to the conventional migration methods, it can compensate for the amplitude loss in the migrated images because of the strong subsurface attenuation and can produce reflectors that are accurately positioned in depth. However, the adjoint Q propagators used for backward propagating the residual data are also attenuative. Thus, the inverted images from Q-LSRTM are often observed to have lower resolution when compared to the benchmark acoustic LSRTM images from acoustic data. To increase the resolution and accelerate the convergence of Q-LSRTM, we propose using viscoacoustic deblurring filters as a preconditioner for Q-LSRTM. These filters can be estimated by matching a simulated migration image to its reference reflectivity model. Numerical tests on synthetic and field data demonstrate that Q-LSRTM combined with viscoacoustic deblurring filters can produce images with higher resolution and more balanced amplitudes than images from acoustic RTM, acoustic LSRTM and Q-LSRTM when there is strong attenuation in the background medium. The proposed preconditioning method is also shown to improve the convergence rate of Q-LSRTM by more than 30 percent in some cases and significantly compensate for the lossy artifacts in RTM images.

Branch-pipe-routing approach for ships using improved genetic algorithm

Science.gov (United States)

Sui, Haiteng; Niu, Wentie

2016-09-01

Branch-pipe routing plays fundamental and critical roles in ship-pipe design. The branch-pipe-routing problem is a complex combinatorial optimization problem and is thus difficult to solve when depending only on human experts. A modified genetic-algorithm-based approach is proposed in this paper to solve this problem. The simplified layout space is first divided into threedimensional (3D) grids to build its mathematical model. Branch pipes in layout space are regarded as a combination of several two-point pipes, and the pipe route between two connection points is generated using an improved maze algorithm. The coding of branch pipes is then defined, and the genetic operators are devised, especially the complete crossover strategy that greatly accelerates the convergence speed. Finally, simulation tests demonstrate the performance of proposed method.

Tissue stiffening coordinates morphogenesis by triggering collective cell migration in vivo.

Science.gov (United States)

Barriga, Elias H; Franze, Kristian; Charras, Guillaume; Mayor, Roberto

2018-02-22

Collective cell migration is essential for morphogenesis, tissue remodelling and cancer invasion. In vivo, groups of cells move in an orchestrated way through tissues. This movement involves mechanical as well as molecular interactions between cells and their environment. While the role of molecular signals in collective cell migration is comparatively well understood, how tissue mechanics influence collective cell migration in vivo remains unknown. Here we investigated the importance of mechanical cues in the collective migration of the Xenopus laevis neural crest cells, an embryonic cell population whose migratory behaviour has been likened to cancer invasion. We found that, during morphogenesis, the head mesoderm underlying the cephalic neural crest stiffens. This stiffening initiates an epithelial-to-mesenchymal transition in neural crest cells and triggers their collective migration. To detect changes in their mechanical environment, neural crest cells use mechanosensation mediated by the integrin-vinculin-talin complex. By performing mechanical and molecular manipulations, we show that mesoderm stiffening is necessary and sufficient to trigger neural crest migration. Finally, we demonstrate that convergent extension of the mesoderm, which starts during gastrulation, leads to increased mesoderm stiffness by increasing the cell density underneath the neural crest. These results show that convergent extension of the mesoderm has a role as a mechanical coordinator of morphogenesis, and reveal a link between two apparently unconnected processes-gastrulation and neural crest migration-via changes in tissue mechanics. Overall, we demonstrate that changes in substrate stiffness can trigger collective cell migration by promoting epithelial-to-mesenchymal transition in vivo. More broadly, our results raise the idea that tissue mechanics combines with molecular effectors to coordinate morphogenesis.

Heading south or north: novel insights on European silver eel Anguilla anguilla migration in the North Sea

NARCIS (Netherlands)

Huisman, Jeroen; Verhelst, Pieterjan; Verhelst, Pieterjan; Deneudt, K.; Goethals, Peter; Moens, Tom; Nagelkerke, Leopold A.J.; Nolting, Carsten; Reubens, Jan; Schollema, Peter Paul; Winter, Hendrik V.; Mouton, Ans

2016-01-01

The European eel Anguilla anguilla L. is a critically endangered fish species that migrates from coastal and freshwater habitats to the Sargasso Sea to spawn. However, the exact migration routes and destination of European eel are still unknown. We are the first to observe southward migrating

Modelling the adaptive behaviour of migrating white storks

NARCIS (Netherlands)

Shamoun-Baranes, J.; van Loon, E.E.; Bouten, W.

2006-01-01

White storks (Ciconia ciconia) are soaring migrants whose western Palearctic populations use several migration routes, concentrating mainly over Gibraltar and Israel to cross between their Palearctic breeding grounds and wintering grounds in Africa. A wealth of data has been collected during the

Geomagnetic imprinting predicts spatio-temporal variation in homing migration of pink and sockeye salmon

Science.gov (United States)

Putman, Nathan F.; Jenkins, Erica S.; Michielsens, Catherine G. J.; Noakes, David L. G.

2014-01-01

Animals navigate using a variety of sensory cues, but how each is weighted during different phases of movement (e.g. dispersal, foraging, homing) is controversial. Here, we examine the geomagnetic and olfactory imprinting hypotheses of natal homing with datasets that recorded variation in the migratory routes of sockeye (Oncorhynchus nerka) and pink (Oncorhynchus gorbuscha) salmon returning from the Pacific Ocean to the Fraser River, British Columbia. Drift of the magnetic field (i.e. geomagnetic imprinting) uniquely accounted for 23.2% and 44.0% of the variation in migration routes for sockeye and pink salmon, respectively. Ocean circulation (i.e. olfactory imprinting) predicted 6.1% and 0.1% of the variation in sockeye and pink migration routes, respectively. Sea surface temperature (a variable influencing salmon distribution but not navigation, directly) accounted for 13.0% of the variation in sockeye migration but was unrelated to pink migration. These findings suggest that geomagnetic navigation plays an important role in long-distance homing in salmon and that consideration of navigation mechanisms can aid in the management of migratory fishes by better predicting movement patterns. Finally, given the diversity of animals that use the Earth's magnetic field for navigation, geomagnetic drift may provide a unifying explanation for spatio-temporal variation in the movement patterns of many species. PMID:25056214

DARAL: A Dynamic and Adaptive Routing Algorithm for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Francisco José Estévez

2016-06-01

Full Text Available The evolution of Smart City projects is pushing researchers and companies to develop more efficient embedded hardware and also more efficient communication technologies. These communication technologies are the focus of this work, presenting a new routing algorithm based on dynamically-allocated sub-networks and node roles. Among these features, our algorithm presents a fast set-up time, a reduced overhead and a hierarchical organization, which allows for the application of complex management techniques. This work presents a routing algorithm based on a dynamically-allocated hierarchical clustering, which uses the link quality indicator as a reference parameter, maximizing the network coverage and minimizing the control message overhead and the convergence time. The present work based its test scenario and analysis in the density measure, considered as a node degree. The routing algorithm is compared with some of the most well known routing algorithms for different scenario densities.

Analysis of genomic data as an approach to understanding migration in song birds

OpenAIRE

Boss, John

2015-01-01

Many species of birds migrate every year thousands of kilometers, relying on sight, memory, magnetic sensors and instincts to find their way across continents. Many juvenile birds travel complicated migration routes without the guidance of more experienced adults. To successfully accomplish this they need instincts that utilizes multiple navigational senses together with a time dependent schedule. Little is known of the genetics behind migration behavior and which cellular processes are invol...

Simulating the Oceanic Migration of Silver Japanese Eels.

Directory of Open Access Journals (Sweden)

Yu-Lin Chang

Full Text Available The oceanic migration of silver Japanese eels starts from their continental growth habitats in East Asia and ends at the spawning area near the West Mariana Ridge seamount chain. However, the actual migration routes remain unknown. In this study, we examined the possible oceanic migration routes and strategies of silver Japanese eels using a particle tracking method in which virtual eels (v-eels were programmed to move vertically and horizontally in an ocean circulation model (Japan Coastal Ocean Predictability Experiment 2, JCOPE2. Four horizontal swimming strategies were tested: random heading, true navigation (readjusted heading, orientation toward the spawning area (fixed heading, and swimming against the Kuroshio. We found that all strategies, except random swimming, allowed v-eels swimming at 0.65 m s-1 to reach the spawning area within eight months after their departure from the south coast of Japan (end of the spawning season. The estimated minimum swimming speed required to reach the area spawning within eight months was 0.1 m s-1 for true navigation, 0.12 m s-1 for constant compass heading, and 0.35 m s-1 for swimming against the Kuroshio. The lowest swimming speed estimated from tracked Japanese eels at sea was 0.03 m.s-1, which would not allow them to reach the spawning area within eight months, through any of the tested orientation strategies. Our numerical experiments also showed that ocean circulation significantly affected the migration of Japanese v-eels. A strong Kuroshio could advect v-eels further eastward. In addition, western Pacific ocean currents accelerated the migration of navigating v-eels. The migration duration was shortened in years with a stronger southward flow, contributed by a stronger recirculation south of Japan, an enhanced subtropical gyre, or a higher southward Kuroshio velocity.

Simulating the Oceanic Migration of Silver Japanese Eels.

Science.gov (United States)

Chang, Yu-Lin; Miyazawa, Yasumasa; Béguer-Pon, Mélanie

2016-01-01

The oceanic migration of silver Japanese eels starts from their continental growth habitats in East Asia and ends at the spawning area near the West Mariana Ridge seamount chain. However, the actual migration routes remain unknown. In this study, we examined the possible oceanic migration routes and strategies of silver Japanese eels using a particle tracking method in which virtual eels (v-eels) were programmed to move vertically and horizontally in an ocean circulation model (Japan Coastal Ocean Predictability Experiment 2, JCOPE2). Four horizontal swimming strategies were tested: random heading, true navigation (readjusted heading), orientation toward the spawning area (fixed heading), and swimming against the Kuroshio. We found that all strategies, except random swimming, allowed v-eels swimming at 0.65 m s-1 to reach the spawning area within eight months after their departure from the south coast of Japan (end of the spawning season). The estimated minimum swimming speed required to reach the area spawning within eight months was 0.1 m s-1 for true navigation, 0.12 m s-1 for constant compass heading, and 0.35 m s-1 for swimming against the Kuroshio. The lowest swimming speed estimated from tracked Japanese eels at sea was 0.03 m.s-1, which would not allow them to reach the spawning area within eight months, through any of the tested orientation strategies. Our numerical experiments also showed that ocean circulation significantly affected the migration of Japanese v-eels. A strong Kuroshio could advect v-eels further eastward. In addition, western Pacific ocean currents accelerated the migration of navigating v-eels. The migration duration was shortened in years with a stronger southward flow, contributed by a stronger recirculation south of Japan, an enhanced subtropical gyre, or a higher southward Kuroshio velocity.

Plane-wave least-squares reverse-time migration

KAUST Repository

Dai, Wei

2013-06-03

A plane-wave least-squares reverse-time migration (LSRTM) is formulated with a new parameterization, where the migration image of each shot gather is updated separately and an ensemble of prestack images is produced along with common image gathers. The merits of plane-wave prestack LSRTM are the following: (1) plane-wave prestack LSRTM can sometimes offer stable convergence even when the migration velocity has bulk errors of up to 5%; (2) to significantly reduce computation cost, linear phase-shift encoding is applied to hundreds of shot gathers to produce dozens of plane waves. Unlike phase-shift encoding with random time shifts applied to each shot gather, plane-wave encoding can be effectively applied to data with a marine streamer geometry. (3) Plane-wave prestack LSRTM can provide higher-quality images than standard reverse-time migration. Numerical tests on the Marmousi2 model and a marine field data set are performed to illustrate the benefits of plane-wave LSRTM. Empirical results show that LSRTM in the plane-wave domain, compared to standard reversetime migration, produces images efficiently with fewer artifacts and better spatial resolution. Moreover, the prestack image ensemble accommodates more unknowns to makes it more robust than conventional least-squares migration in the presence of migration velocity errors. © 2013 Society of Exploration Geophysicists.

Weak Convergence and Fluid Limits in Optimal Time-to-Empty Queueing Control Problems

Energy Technology Data Exchange (ETDEWEB)

Day, Martin V., E-mail: day@math.vt.edu [Virginia Tech, Department of Mathematics (United States)

2011-12-15

We consider a class of controlled queue length processes, in which the control allocates each server's effort among the several classes of customers requiring its service. Served customers are routed through the network according to (prescribed) routing probabilities. In the fluid rescaling, X{sup n}(t) = 1/nX(nt) , we consider the optimal control problem of minimizing the integral of an undiscounted positive running cost until the first time that X{sup n}=0. Our main result uses weak convergence ideas to show that the optimal value functions V{sup n} of the stochastic control problems for X{sup n}(t) converge (as n{yields}{infinity}) to the optimal value V of a control problem for the limiting fluid process. This requires certain equicontinuity and boundedness hypotheses on (V{sup n}). We observe that these are essentially the same hypotheses that would be needed for the Barles-Perthame approach in terms of semicontinuous viscosity solutions. Sufficient conditions for these equicontinuity and boundedness properties are briefly discussed.

Converging flow joint insert system at an intersection between adjacent transitions extending between a combustor and a turbine assembly in a gas turbine engine

Science.gov (United States)

Wiebe, David J.; Carlson, Andrew; Stoker, Kyle C.

2017-10-31

A transition duct system for routing a gas flow in a combustion turbine engine is provided. The transition duct system includes one or more converging flow joint inserts forming a trailing edge at an intersection between adjacent transition ducts. The converging flow joint insert may be contained within a converging flow joint insert receiver and may be disconnected from the transition duct bodies by which the converging flow joint insert is positioned. Being disconnected eliminates stress formation within the converging flow joint insert, thereby enhancing the life of the insert. The converging flow joint insert may be removable such that the insert can be replaced once worn beyond design limits.

An Autonomous Self-Aware and Adaptive Fault Tolerant Routing Technique for Wireless Sensor Networks.

Science.gov (United States)

Abba, Sani; Lee, Jeong-A

2015-08-18

We propose an autonomous self-aware and adaptive fault-tolerant routing technique (ASAART) for wireless sensor networks. We address the limitations of self-healing routing (SHR) and self-selective routing (SSR) techniques for routing sensor data. We also examine the integration of autonomic self-aware and adaptive fault detection and resiliency techniques for route formation and route repair to provide resilience to errors and failures. We achieved this by using a combined continuous and slotted prioritized transmission back-off delay to obtain local and global network state information, as well as multiple random functions for attaining faster routing convergence and reliable route repair despite transient and permanent node failure rates and efficient adaptation to instantaneous network topology changes. The results of simulations based on a comparison of the ASAART with the SHR and SSR protocols for five different simulated scenarios in the presence of transient and permanent node failure rates exhibit a greater resiliency to errors and failure and better routing performance in terms of the number of successfully delivered network packets, end-to-end delay, delivered MAC layer packets, packet error rate, as well as efficient energy conservation in a highly congested, faulty, and scalable sensor network.

Geomagnetic imprinting predicts spatio-temporal variation in homing migration of pink and sockeye salmon.

Science.gov (United States)

Putman, Nathan F; Jenkins, Erica S; Michielsens, Catherine G J; Noakes, David L G

2014-10-06

Animals navigate using a variety of sensory cues, but how each is weighted during different phases of movement (e.g. dispersal, foraging, homing) is controversial. Here, we examine the geomagnetic and olfactory imprinting hypotheses of natal homing with datasets that recorded variation in the migratory routes of sockeye (Oncorhynchus nerka) and pink (Oncorhynchus gorbuscha) salmon returning from the Pacific Ocean to the Fraser River, British Columbia. Drift of the magnetic field (i.e. geomagnetic imprinting) uniquely accounted for 23.2% and 44.0% of the variation in migration routes for sockeye and pink salmon, respectively. Ocean circulation (i.e. olfactory imprinting) predicted 6.1% and 0.1% of the variation in sockeye and pink migration routes, respectively. Sea surface temperature (a variable influencing salmon distribution but not navigation, directly) accounted for 13.0% of the variation in sockeye migration but was unrelated to pink migration. These findings suggest that geomagnetic navigation plays an important role in long-distance homing in salmon and that consideration of navigation mechanisms can aid in the management of migratory fishes by better predicting movement patterns. Finally, given the diversity of animals that use the Earth's magnetic field for navigation, geomagnetic drift may provide a unifying explanation for spatio-temporal variation in the movement patterns of many species. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

A pilgrim's progress: Seeking meaning in primordial germ cell migration.

Science.gov (United States)

Cantú, Andrea V; Laird, Diana J

2017-10-01

Comparative studies of primordial germ cell (PGC) development across organisms in many phyla reveal surprising diversity in the route of migration, timing and underlying molecular mechanisms, suggesting that the process of migration itself is conserved. However, beyond the perfunctory transport of cellular precursors to their later arising home of the gonads, does PGC migration serve a function? Here we propose that the process of migration plays an additional role in quality control, by eliminating PGCs incapable of completing migration as well as through mechanisms that favor PGCs capable of responding appropriately to migration cues. Focusing on PGCs in mice, we explore evidence for a selective capacity of migration, considering the tandem regulation of proliferation and migration, cell-intrinsic and extrinsic control, the potential for tumors derived from failed PGC migrants, the potential mechanisms by which migratory PGCs vary in their cellular behaviors, and corresponding effects on development. We discuss the implications of a selective role of PGC migration for in vitro gametogenesis. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Geography, Islands and Migration in an Era of Global Mobility

Directory of Open Access Journals (Sweden)

Russell King

2009-05-01

Full Text Available This paper examines the changing role of islands in the age of globalization and in an era of enhanced and diversified mobility. There are many types of islands, many metaphors of insularity, and many types of migration, so the interactions are far from simple. The ‘mobilities turn’ in migration studies recognizes the diversification in motivations and time-space regimes of human migration. After brief reviews of island studies and of migration studies, and the power of geography to capture and distil the interdisciplinarity and relationality of these two study domains, the paper explores various facets of the generally intense engagement that islands have with migration. Two particular scenarios are identified for islands and migration in the global era: the heuristic role of islands as ‘spatial laboratories’ for the study of diverse migration processes in microcosm; and the way in which, especially in the Mediterranean and near-Atlantic regions, islands have become critical locations in the geopolitics of irregular migration routes. The case of Malta is taken to illustrate some of these new insular migration dynamics.

Joint Power Charging and Routing in Wireless Rechargeable Sensor Networks.

Science.gov (United States)

Jia, Jie; Chen, Jian; Deng, Yansha; Wang, Xingwei; Aghvami, Abdol-Hamid

2017-10-09

The development of wireless power transfer (WPT) technology has inspired the transition from traditional battery-based wireless sensor networks (WSNs) towards wireless rechargeable sensor networks (WRSNs). While extensive efforts have been made to improve charging efficiency, little has been done for routing optimization. In this work, we present a joint optimization model to maximize both charging efficiency and routing structure. By analyzing the structure of the optimization model, we first decompose the problem and propose a heuristic algorithm to find the optimal charging efficiency for the predefined routing tree. Furthermore, by coding the many-to-one communication topology as an individual, we further propose to apply a genetic algorithm (GA) for the joint optimization of both routing and charging. The genetic operations, including tree-based recombination and mutation, are proposed to obtain a fast convergence. Our simulation results show that the heuristic algorithm reduces the number of resident locations and the total moving distance. We also show that our proposed algorithm achieves a higher charging efficiency compared with existing algorithms.

A Hybrid Chaos-Particle Swarm Optimization Algorithm for the Vehicle Routing Problem with Time Window

Directory of Open Access Journals (Sweden)

Qi Hu

2013-04-01

Full Text Available State-of-the-art heuristic algorithms to solve the vehicle routing problem with time windows (VRPTW usually present slow speeds during the early iterations and easily fall into local optimal solutions. Focusing on solving the above problems, this paper analyzes the particle encoding and decoding strategy of the particle swarm optimization algorithm, the construction of the vehicle route and the judgment of the local optimal solution. Based on these, a hybrid chaos-particle swarm optimization algorithm (HPSO is proposed to solve VRPTW. The chaos algorithm is employed to re-initialize the particle swarm. An efficient insertion heuristic algorithm is also proposed to build the valid vehicle route in the particle decoding process. A particle swarm premature convergence judgment mechanism is formulated and combined with the chaos algorithm and Gaussian mutation into HPSO when the particle swarm falls into the local convergence. Extensive experiments are carried out to test the parameter settings in the insertion heuristic algorithm and to evaluate that they are corresponding to the data’s real-distribution in the concrete problem. It is also revealed that the HPSO achieves a better performance than the other state-of-the-art algorithms on solving VRPTW.

Satellite tracking of the migration of Whooper Swans Cygnus cygnus wintering in Japan

Science.gov (United States)

Shimada, Tetsuo; Yamaguchi, Noriyuki M.; Hijikata, N.; Hiraoka, Emiko N.; Hupp, Jerry; Flint, Paul L.; Tokita, Ken-ichi; Fujita, Go; Uchida, Kiyoshi; Sato, F.; Kurechi, Masayuki; Pearce, John M.; Ramey, Andy M.; Higuchi, Hiroyoshi

2014-01-01

We satellite-tracked Whooper Swans Cygnus cygnus wintering in northern Japan to document their migration routes and timing, and to identify breeding areas. From 47 swans that we marked at Lake Izunuma-Uchinuma, Miyagi Prefecture, northeast Honshu, and at Lake Kussharo, east Hokkaido, we observed 57 spring and 33 autumn migrations from 2009-2012. In spring, swans migrated north along Sakhalin Island from eastern Hokkaido using stopovers in Sakhalin, at the mouth of the Amur River and in northern coastal areas of the Sea of Okhotsk. They ultimately reached molting/breedmg areas along the Indigirka River and the lower Kolyma River in northern Russia. In autumn, the swans basically reversed the spring migration routes. We identified northern Honshu, eastern Hokkaido, coastal areas in Sakhalin, the lower Amur River and northern coastal areas of the Sea of Okhotsk as the most frequent stopover sites, and the middle reaches of the Indigirka and the lower Kolyma River as presumed breeding sites. Our results are helpful in understanding the distribution of the breeding and stopover sites of Whooper Swans wintering in Japan and in identifying their major migration habitats. Our findings contribute to understanding the potential transmission process of avian influenza viruses potentially carried by swans, and provide information necessary to conserve Whooper Swans in East Asia.

Stable and efficient Q-compensated least-squares migration with compressive sensing, sparsity-promoting, and preconditioning

Science.gov (United States)

Chai, Xintao; Wang, Shangxu; Tang, Genyang; Meng, Xiangcui

2017-10-01

The anelastic effects of subsurface media decrease the amplitude and distort the phase of propagating wave. These effects, also referred to as the earth's Q filtering effects, diminish seismic resolution. Ignoring anelastic effects during seismic imaging process generates an image with reduced amplitude and incorrect position of reflectors, especially for highly absorptive media. The numerical instability and the expensive computational cost are major concerns when compensating for anelastic effects during migration. We propose a stable and efficient Q-compensated imaging methodology with compressive sensing, sparsity-promoting, and preconditioning. The stability is achieved by using the Born operator for forward modeling and the adjoint operator for back propagating the residual wavefields. Constructing the attenuation-compensated operators by reversing the sign of attenuation operator is avoided. The method proposed is always stable. To reduce the computational cost that is proportional to the number of wave-equation to be solved (thereby the number of frequencies, source experiments, and iterations), we first subsample over both frequencies and source experiments. We mitigate the artifacts caused by the dimensionality reduction via promoting sparsity of the imaging solutions. We further employ depth- and Q-preconditioning operators to accelerate the convergence rate of iterative migration. We adopt a relatively simple linearized Bregman method to solve the sparsity-promoting imaging problem. Singular value decomposition analysis of the forward operator reveals that attenuation increases the condition number of migration operator, making the imaging problem more ill-conditioned. The visco-acoustic imaging problem converges slower than the acoustic case. The stronger the attenuation, the slower the convergence rate. The preconditioning strategy evidently decreases the condition number of migration operator, which makes the imaging problem less ill-conditioned and

Can a foreign body migrate against natural body barriers?

African Journals Online (AJOL)

Amr A. Arafat, Abdel-Hady M. Taha, Ahmed G. Elkhouly and Abdelmotagaly A. Elgalad. Pericardial foreign bodies (FBs) are a rare cause of chest pain in children. They can reach the pericardium through several routes including direct or iatrogenic implantation, transbronchial or transesophageal migration of inhaled or.

Energy Reserves, Information Need and a Pinch of Personality Determine Decision-Making on Route in Partially Migratory Blue Tits.

Directory of Open Access Journals (Sweden)

Anna L K Nilsson

Full Text Available In facultative partial migrants some individuals in a population are migratory and others are resident and individuals decide each year anew which strategy to choose. While the proportion of birds migrating is in part determined by environmental conditions and competitive abilities, the timing of individual departure and behaviours on route are little understood. Individuals encounter different environmental conditions when migrating earlier or later. Based on cost/ benefit considerations we tested whether behaviours on route were affected by time constraints, personality and/or age in a partially migrating population of Blue tits (Cyanistes caeruleus. We captured female Blue tits on migration at the Southern tip of Sweden during early, peak and late migration and measured latency to feed in an unfamiliar environment, exploration of a novel object and hesitation to feed beside a novel object (neophobia. Lean birds and birds with long wings started feeding earlier when released into the cage indicating that foraging decisions were mainly determined by energetic needs (lean and large birds. However, juveniles commenced feeding later with progression of the migratory season in concordance with predictions about personality effects. Furthermore, lean birds started to explore earlier than birds with larger fat reserves again indicating an effect of maintaining threshold energy reserves. Moreover, late migrating juveniles, started to explore earlier than early migrating juveniles possibly due to time constraints to find high-quality foraging patches or a suitable winter home. Finally, neophobia did not change over the migratory season indicating that this behaviour is not compromised by time constraints. The results overall indicate that decisions on route are mainly governed by energetic requirements and current needs to learn about the environment and only to a small extent by differences in personality.

Energy Reserves, Information Need and a Pinch of Personality Determine Decision-Making on Route in Partially Migratory Blue Tits.

Science.gov (United States)

Nilsson, Anna L K; Nilsson, Jan-Åke; Mettke-Hofmann, Claudia

2016-01-01

In facultative partial migrants some individuals in a population are migratory and others are resident and individuals decide each year anew which strategy to choose. While the proportion of birds migrating is in part determined by environmental conditions and competitive abilities, the timing of individual departure and behaviours on route are little understood. Individuals encounter different environmental conditions when migrating earlier or later. Based on cost/ benefit considerations we tested whether behaviours on route were affected by time constraints, personality and/or age in a partially migrating population of Blue tits (Cyanistes caeruleus). We captured female Blue tits on migration at the Southern tip of Sweden during early, peak and late migration and measured latency to feed in an unfamiliar environment, exploration of a novel object and hesitation to feed beside a novel object (neophobia). Lean birds and birds with long wings started feeding earlier when released into the cage indicating that foraging decisions were mainly determined by energetic needs (lean and large birds). However, juveniles commenced feeding later with progression of the migratory season in concordance with predictions about personality effects. Furthermore, lean birds started to explore earlier than birds with larger fat reserves again indicating an effect of maintaining threshold energy reserves. Moreover, late migrating juveniles, started to explore earlier than early migrating juveniles possibly due to time constraints to find high-quality foraging patches or a suitable winter home. Finally, neophobia did not change over the migratory season indicating that this behaviour is not compromised by time constraints. The results overall indicate that decisions on route are mainly governed by energetic requirements and current needs to learn about the environment and only to a small extent by differences in personality.

Multiple depots vehicle routing based on the ant colony with the genetic algorithm

Directory of Open Access Journals (Sweden)

ChunYing Liu

2013-09-01

Full Text Available Purpose: the distribution routing plans of multi-depots vehicle scheduling problem will increase exponentially along with the adding of customers. So, it becomes an important studying trend to solve the vehicle scheduling problem with heuristic algorithm. On the basis of building the model of multi-depots vehicle scheduling problem, in order to improve the efficiency of the multiple depots vehicle routing, the paper puts forward a fusion algorithm on multiple depots vehicle routing based on the ant colony algorithm with genetic algorithm. Design/methodology/approach: to achieve this objective, the genetic algorithm optimizes the parameters of the ant colony algorithm. The fusion algorithm on multiple depots vehicle based on the ant colony algorithm with genetic algorithm is proposed. Findings: simulation experiment indicates that the result of the fusion algorithm is more excellent than the other algorithm, and the improved algorithm has better convergence effective and global ability. Research limitations/implications: in this research, there are some assumption that might affect the accuracy of the model such as the pheromone volatile factor, heuristic factor in each period, and the selected multiple depots. These assumptions can be relaxed in future work. Originality/value: In this research, a new method for the multiple depots vehicle routing is proposed. The fusion algorithm eliminate the influence of the selected parameter by optimizing the heuristic factor, evaporation factor, initial pheromone distribute, and have the strong global searching ability. The Ant Colony algorithm imports cross operator and mutation operator for operating the first best solution and the second best solution in every iteration, and reserves the best solution. The cross and mutation operator extend the solution space and improve the convergence effective and the global ability. This research shows that considering both the ant colony and genetic algorithm

An Autonomous Self-Aware and Adaptive Fault Tolerant Routing Technique for Wireless Sensor Networks

Science.gov (United States)

Abba, Sani; Lee, Jeong-A

2015-01-01

We propose an autonomous self-aware and adaptive fault-tolerant routing technique (ASAART) for wireless sensor networks. We address the limitations of self-healing routing (SHR) and self-selective routing (SSR) techniques for routing sensor data. We also examine the integration of autonomic self-aware and adaptive fault detection and resiliency techniques for route formation and route repair to provide resilience to errors and failures. We achieved this by using a combined continuous and slotted prioritized transmission back-off delay to obtain local and global network state information, as well as multiple random functions for attaining faster routing convergence and reliable route repair despite transient and permanent node failure rates and efficient adaptation to instantaneous network topology changes. The results of simulations based on a comparison of the ASAART with the SHR and SSR protocols for five different simulated scenarios in the presence of transient and permanent node failure rates exhibit a greater resiliency to errors and failure and better routing performance in terms of the number of successfully delivered network packets, end-to-end delay, delivered MAC layer packets, packet error rate, as well as efficient energy conservation in a highly congested, faulty, and scalable sensor network. PMID:26295236

Security-Oriented and Load-Balancing Wireless Data Routing Game in the Integration of Advanced Metering Infrastructure Network in Smart Grid

Energy Technology Data Exchange (ETDEWEB)

He, Fulin; Cao, Yang; Zhang, Jun Jason; Wei, Jiaolong; Zhang, Yingchen; Muljadi, Eduard; Gao, Wenzhong

2016-11-21

Ensuring flexible and reliable data routing is indispensable for the integration of Advanced Metering Infrastructure (AMI) networks, we propose a secure-oriented and load-balancing wireless data routing scheme. A novel utility function is designed based on security routing scheme. Then, we model the interactive security-oriented routing strategy among meter data concentrators or smart grid meters as a mixed-strategy network formation game. Finally, such problem results in a stable probabilistic routing scheme with proposed distributed learning algorithm. One contributions is that we studied that different types of applications affect the routing selection strategy and the strategy tendency. Another contributions is that the chosen strategy of our mixed routing can adaptively to converge to a new mixed strategy Nash equilibrium (MSNE) during the learning process in the smart grid.

Public Transport Route Finding using a Hybrid Genetic Algorithm

OpenAIRE

Liviu Adrian COTFAS; Andreea DIOSTEANU

2011-01-01

In this paper we present a public transport route finding solution based on a hybrid genetic algorithm. The algorithm uses two heuristics that take into consideration the number of trans-fers and the remaining distance to the destination station in order to improve the convergence speed. The interface of the system uses the latest web technologies to offer both portability and advanced functionality. The approach has been evaluated using the data for the Bucharest public transport network.

Hemispheric-scale wind selection facilitates bar-tailed godwit circum-migration of the Pacific

Science.gov (United States)

Gill, Robert E.; Douglas, David C.; Handel, Colleen M.; Tibbitts, T. Lee; Hufford, Gary; Piersma, Theunis

2014-01-01

The annual 29 000 km long migration of the bar-tailed godwit, Limosa lapponica baueri, around the Pacific Ocean traverses what is arguably the most complex and seasonally structured atmospheric setting on Earth. Faced with marked variation in wind regimes and storm conditions across oceanic migration corridors, individuals must make critical decisions about when and where to fly during nonstop flights of a week's duration or longer. At a minimum, their decisions will affect wind profitability and thus reduce energetic costs of migration; in the extreme, poor decisions or unpredictable weather events will risk survival. We used satellite telemetry to track the annual migration of 24 bar-tailed godwits and analysed their flight performance relative to wind conditions during three major migration legs between nonbreeding grounds in New Zealand and breeding grounds in Alaska. Because flight altitudes of birds en route were unknown, we modelled flight efficiency at six geopotential heights across each migratory segment. Birds selected departure dates when atmospheric conditions conferred the greatest wind assistance both at departure and throughout their flights. This behaviour suggests that there exists a cognitive mechanism, heretofore unknown among migratory birds, that allows godwits to assess changes in weather conditions that are linked (i.e. teleconnected) across widely separated atmospheric regions. Godwits also showed adaptive flexibility in their response not only to cues related to seasonal changes in macrometeorology, such as spatial shifting of storm tracks and temporal periods of cyclogenesis, but also to cues associated with stochastic events, especially at departure sites. Godwits showed limits to their response behaviours, however, especially relative to rapidly developing stochastic events while en route. We found that flight efficiency depended significantly upon altitude and hypothesize that godwits exhibit further adaptive flexibility by varying

Convergence accommodation to convergence CA/C ratio: convergence versus divergence.

Science.gov (United States)

Simmons, Joshua M; Firth, Alison Y

2014-09-01

To determine whether the convergence accommodation to convergence (CA/C) ratio during divergence with base-in (BI) prisms is of a similar or different magnitude to that measured during convergence with base-out (BO) prisms. Eighteen participants with normal binocular single vision were recruited. The participants viewed a pseudo-Gaussian target, which consisted of a light emitting diode (LED) behind a diffusing screen at 40 cm. After 5 minutes of dark adaptation, the refractive status of the eye was measured without any prism using a Shin-Nippon SRW-5000 autorefractor. The participant held the selected prism (5Δ or 10Δ BO or BI, counterbalanced) in front of their right eye and obtained a single, fused image of the target while refractive measures were taken with each. A 30-second rest period was given between measurements. The mean age of the participants was 20.6±3.22 years. The mean CA/C ratios for the 5Δ BO, 10Δ BO, 5Δ BI, and 10Δ BI were 0.108 (±0.074) D/Δ, 0.110 (±0.056) D/Δ, 0.100 (±0.090) D/Δ, and 0.089 (±0.055) D/Δ, respectively. A 2-factor repeated measures ANOVA found that the CA/C ratio did not significantly change with differing levels of prism-induced convergence and divergence (p=0.649). Change in accommodation induced by manipulating vergence is similar whether convergence or divergence are induced. The CA/C ratio did not show any change with differing levels of prism-induced convergence and divergence.

Plasmodium spp. in raptors on the Eurasian-African migration route.

Science.gov (United States)

Paperna, I; Yosef, R; Landau, I

2007-12-01

Examination of blood smears obtained from raptors trapped while on migration at Eilat, Israel, demonstrated Plasmodium infection in Accipiter brevipes and Buteo buteo. The following species are described, from A. brevipes: Plasmodium alloelongatum n. sp., P. accipiteris n. sp. and from B. buteo: P. buteonis n. sp. and Plasmodium sp. for which we lack sufficient data for adequate species description. Overall prevalence of infection with Plasmodium spp. was very low: among 38 examined A. brevipes 5% and among 56 B. buteo 3.6%.

Narrow-front loop migration in a population of the common cuckoo Cuculus canorus, as revealed by satellite telemetry

NARCIS (Netherlands)

Willemoes, Mikkel; Strandberg, Roine; Klaassen, Raymond H. G.; Tottrup, Anders P.; Vardanis, Yannis; Howey, Paul W.; Thorup, Kasper; Wikelski, Martin; Alerstam, Thomas

2014-01-01

Narrow migration corridors known in diurnal, social migrants such as raptors, storks and geese are thought to be caused by topographical leading line effects in combination with learning detailed routes across generations. Here, we document narrow-front migration in a nocturnal, solitary migrant,

Least-squares migration of multisource data with a deblurring filter

KAUST Repository

Dai, Wei; Wang, Xin; Schuster, Gerard T.

2011-01-01

Least-squares migration (LSM) has been shown to be able to produce high-quality migration images, but its computational cost is considered to be too high for practical imaging. We have developed a multisource least-squares migration algorithm (MLSM) to increase the computational efficiency by using the blended sources processing technique. To expedite convergence, a multisource deblurring filter is used as a preconditioner to reduce the data residual. This MLSM algorithm is applicable with Kirchhoff migration, wave-equation migration, or reverse time migration, and the gain in computational efficiency depends on the choice of migration method. Numerical results with Kirchhoff LSM on the 2D SEG/EAGE salt model show that an accurate image is obtained by migrating a supergather of 320 phase-encoded shots. When the encoding functions are the same for every iteration, the input/output cost of MLSM is reduced by 320 times. Empirical results show that the crosstalk noise introduced by blended sources is more effectively reduced when the encoding functions are changed at every iteration. The analysis of signal-to-noise ratio (S/N) suggests that not too many iterations are needed to enhance the S/N to an acceptable level. Therefore, when implemented with wave-equation migration or reverse time migration methods, the MLSM algorithm can be more efficient than the conventional migration method. © 2011 Society of Exploration Geophysicists.

Least-squares migration of multisource data with a deblurring filter

KAUST Repository

Dai, Wei

2011-09-01

Least-squares migration (LSM) has been shown to be able to produce high-quality migration images, but its computational cost is considered to be too high for practical imaging. We have developed a multisource least-squares migration algorithm (MLSM) to increase the computational efficiency by using the blended sources processing technique. To expedite convergence, a multisource deblurring filter is used as a preconditioner to reduce the data residual. This MLSM algorithm is applicable with Kirchhoff migration, wave-equation migration, or reverse time migration, and the gain in computational efficiency depends on the choice of migration method. Numerical results with Kirchhoff LSM on the 2D SEG/EAGE salt model show that an accurate image is obtained by migrating a supergather of 320 phase-encoded shots. When the encoding functions are the same for every iteration, the input/output cost of MLSM is reduced by 320 times. Empirical results show that the crosstalk noise introduced by blended sources is more effectively reduced when the encoding functions are changed at every iteration. The analysis of signal-to-noise ratio (S/N) suggests that not too many iterations are needed to enhance the S/N to an acceptable level. Therefore, when implemented with wave-equation migration or reverse time migration methods, the MLSM algorithm can be more efficient than the conventional migration method. © 2011 Society of Exploration Geophysicists.

Globalising Chinese Migration: New Spaces, New Meanings

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Pál Nyíri

2002-04-01

Full Text Available The paper reviews new trends in international migration from the People’s Republic of China in the last decade, focusing on two aspects: 1 The geographic expansion and merger of formerly distinct translocal migration flows into a global migration system. It includes the opening up of new migration spaces in Eastern Europe and Southeast Asia; increased mobility between destination countries; and increased interchange between different social strata of migrants, from students to illegal workers; 2 A shift in what the social and cultural meaning of migration is to the migrant, to non-migrants, and to elites, which can be described as “upgrading the migrant” (Wang,1998. Various discourses of migration have converged into a highly success-oriented discourse, which reduces the relevance of social background and path of migration. The People’s Republic of China imbues this discourse with tropes of patriotism and development. Concerning the first aspect, the paper problematises the distinction of flows of legal and illegal migrants, students, tourists, and workers, and calls for a holistic approach in studying the configuration of current migration from the PRC. Concerning the second aspect, the paper questions the persistent theory that the PRC as an entity supports emigration, and points out the conflicting interests of various levels and organisations within the state apparatus. At the same time, it recognises that the PRC, like other states, is currently enjoying a honeymoon with state-sanctioned transnationalism, in which migrants are often being more engaged into nation-building and enfranchised as political citizens than are rural non-migrants.

Louse-borne relapsing fever (Borrelia recurrentis) diagnosed in 15 refugees from northeast Africa: epidemiology and preventive control measures, Bavaria, Germany, July to October 2015.

Science.gov (United States)

Hoch, Martin; Wieser, Andreas; Löscher, Thomas; Margos, Gabriele; Pürner, Friedrich; Zühl, Jürgen; Seilmaier, Michael; Balzer, Lukas; Guggemos, Wolfgang; Rack-Hoch, Anita; von Both, Ulrich; Hauptvogel, Katja; Schönberger, Katharina; Hautmann, Wolfgang; Sing, Andreas; Fingerle, Volker

2015-01-01

We report 15 imported louse-borne relapsing fever (LBRF) cases in refugees in Bavaria, Germany. One patient died. Epidemiological findings confirmed that all were young males from the Horn of Africa (12 from Somalia), who had similar migration routes converging in Sudan continuing through Libya and Italy. The majority likely acquired their infection during migration. Healthcare workers should be aware of LBRF in refugees passing through north Africa to ensure correct treatment and preventive measures.

Public Transport Route Finding using a Hybrid Genetic Algorithm

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Liviu Adrian COTFAS

2011-01-01

Full Text Available In this paper we present a public transport route finding solution based on a hybrid genetic algorithm. The algorithm uses two heuristics that take into consideration the number of trans-fers and the remaining distance to the destination station in order to improve the convergence speed. The interface of the system uses the latest web technologies to offer both portability and advanced functionality. The approach has been evaluated using the data for the Bucharest public transport network.

Probing Leader Cells in Endothelial Collective Migration by Plasma Lithography Geometric Confinement.

Science.gov (United States)

Yang, Yongliang; Jamilpour, Nima; Yao, Baoyin; Dean, Zachary S; Riahi, Reza; Wong, Pak Kin

2016-03-03

When blood vessels are injured, leader cells emerge in the endothelium to heal the wound and restore the vasculature integrity. The characteristics of leader cells during endothelial collective migration under diverse physiological conditions, however, are poorly understood. Here we investigate the regulation and function of endothelial leader cells by plasma lithography geometric confinement generated. Endothelial leader cells display an aggressive phenotype, connect to follower cells via peripheral actin cables and discontinuous adherens junctions, and lead migrating clusters near the leading edge. Time-lapse microscopy, immunostaining, and particle image velocimetry reveal that the density of leader cells and the speed of migrating clusters are tightly regulated in a wide range of geometric patterns. By challenging the cells with converging, diverging and competing patterns, we show that the density of leader cells correlates with the size and coherence of the migrating clusters. Collectively, our data provide evidence that leader cells control endothelial collective migration by regualting the migrating clusters.

A Monarch Butterfly Optimization for the Dynamic Vehicle Routing Problem

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Shifeng Chen

2017-09-01

Full Text Available The dynamic vehicle routing problem (DVRP is a variant of the Vehicle Routing Problem (VRP in which customers appear dynamically. The objective is to determine a set of routes that minimizes the total travel distance. In this paper, we propose a monarch butterfly optimization (MBO algorithm to solve DVRPs, utilizing a greedy strategy. Both migration operation and the butterfly adjusting operator only accept the offspring of butterfly individuals that have better fitness than their parents. To improve performance, a later perturbation procedure is implemented, to maintain a balance between global diversification and local intensification. The computational results indicate that the proposed technique outperforms the existing approaches in the literature for average performance by at least 9.38%. In addition, 12 new best solutions were found. This shows that this proposed technique consistently produces high-quality solutions and outperforms other published heuristics for the DVRP.

Present-day African analogue of a pre-European Amazonian floodplain fishery shows convergence in cultural niche construction.

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McKey, Doyle B; Durécu, Mélisse; Pouilly, Marc; Béarez, Philippe; Ovando, Alex; Kalebe, Mashuta; Huchzermeyer, Carl F

2016-12-27

Erickson [Erickson CL (2000) Nature 408 (6809):190-193] interpreted features in seasonal floodplains in Bolivia's Beni savannas as vestiges of pre-European earthen fish weirs, postulating that they supported a productive, sustainable fishery that warranted cooperation in the construction and maintenance of perennial structures. His inferences were bold, because no close ethnographic analogues were known. A similar present-day Zambian fishery, documented here, appears strikingly convergent. The Zambian fishery supports Erickson's key inferences about the pre-European fishery: It allows sustained high harvest levels; weir construction and operation require cooperation; and weirs are inherited across generations. However, our comparison suggests that the pre-European system may not have entailed intensive management, as Erickson postulated. The Zambian fishery's sustainability is based on exploiting an assemblage dominated by species with life histories combining high fecundity, multiple reproductive cycles, and seasonal use of floodplains. As water rises, adults migrate from permanent watercourses into floodplains, through gaps in weirs, to feed and spawn. Juveniles grow and then migrate back to dry-season refuges as water falls. At that moment fishermen set traps in the gaps, harvesting large numbers of fish, mostly juveniles. In nature, most juveniles die during the first dry season, so that their harvest just before migration has limited impact on future populations, facilitating sustainability and the adoption of a fishery based on inherited perennial structures. South American floodplain fishes with similar life histories were the likely targets of the pre-European fishery. Convergence in floodplain fish strategies in these two regions in turn drove convergence in cultural niche construction.

Stochastic time-dependent vehicle routing problem: Mathematical models and ant colony algorithm

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Zhengyu Duan

2015-11-01

Full Text Available This article addresses the stochastic time-dependent vehicle routing problem. Two mathematical models named robust optimal schedule time model and minimum expected schedule time model are proposed for stochastic time-dependent vehicle routing problem, which can guarantee delivery within the time windows of customers. The robust optimal schedule time model only requires the variation range of link travel time, which can be conveniently derived from historical traffic data. In addition, the robust optimal schedule time model based on robust optimization method can be converted into a time-dependent vehicle routing problem. Moreover, an ant colony optimization algorithm is designed to solve stochastic time-dependent vehicle routing problem. As the improvements in initial solution and transition probability, ant colony optimization algorithm has a good performance in convergence. Through computational instances and Monte Carlo simulation tests, robust optimal schedule time model is proved to be better than minimum expected schedule time model in computational efficiency and coping with the travel time fluctuations. Therefore, robust optimal schedule time model is applicable in real road network.

Distribution and Joint Fish-Tag Survival of Juvenile Chinook Salmon Migrating through the Sacramento-San Joaquin River Delta, California, 2008

Science.gov (United States)

Holbrook, Christopher M.; Perry, Russell W.; Adams, Noah S.

2009-01-01

Acoustic telemetry was used to obtain the movement histories of 915 juvenile fall-run Chinook salmon (Oncorhynchus tshawytscha) through the lower San Joaquin River and Sacramento-San Joaquin Delta, California, in 2008. Data were analyzed within a release-recapture framework to estimate survival, route distribution, and detection probabilities among three migration pathways through the Delta. The pathways included the primary route through the San Joaquin River and two less direct routes (Old River and Turner Cut). Strong inferences about survival were limited by premature tag failure, but estimates of fish distribution among migration routes should be unaffected by tag failure. Based on tag failure tests (N = 66 tags), we estimated that only 55-78 percent of the tags used in this study were still functioning when the last fish was detected exiting the study area 15 days after release. Due to premature tag failure, our 'survival' estimates represent the joint probability that both the tag and fish survived, not just survival of fish. Low estimates of fish-tag survival could have been caused by fish mortality or fish travel times that exceeded the life of the tag, but we were unable to differentiate between the two. Fish-tag survival through the Delta (from Durham Ferry to Chipps Island by all routes) ranged from 0.05 +or- 0.01 (SE) to 0.06 +or- 0.01 between the two weekly release groups. Among the three migration routes, fish that remained in the San Joaquin River exhibited the highest joint fish-tag survival (0.09 +or- 0.02) in both weeks, but only 22-33 percent of tagged fish used this route, depending on the week of release. Only 4-10 percent (depending on week) of tagged fish traveled through Turner Cut, but no tagged fish that used this route were detected exiting the Delta. Most fish (63-68 percent, depending on week of release) migrated through Old River, but fish-tag survival through this route (0.05 +or- 0.01) was only about one-half that of fish that

Multiplier convergent series and uniform convergence of mapping ...

Indian Academy of Sciences (India)

MS received 14 April 2011; revised 17 November 2012. Abstract. In this paper, we introduce the frame property of complex sequence sets and study the uniform convergence of nonlinear mapping series in β-dual of spaces consisting of multiplier convergent series. Keywords. Multiplier convergent series; mapping series. 1.

Analysis of parameter estimation and optimization application of ant colony algorithm in vehicle routing problem

Science.gov (United States)

Xu, Quan-Li; Cao, Yu-Wei; Yang, Kun

2018-03-01

Ant Colony Optimization (ACO) is the most widely used artificial intelligence algorithm at present. This study introduced the principle and mathematical model of ACO algorithm in solving Vehicle Routing Problem (VRP), and designed a vehicle routing optimization model based on ACO, then the vehicle routing optimization simulation system was developed by using c ++ programming language, and the sensitivity analyses, estimations and improvements of the three key parameters of ACO were carried out. The results indicated that the ACO algorithm designed in this paper can efficiently solve rational planning and optimization of VRP, and the different values of the key parameters have significant influence on the performance and optimization effects of the algorithm, and the improved algorithm is not easy to locally converge prematurely and has good robustness.

Victim derogation and victim enhancement as alternate routes to system justification.

Science.gov (United States)

Kay, Aaron C; Jost, John T; Young, Sean

2005-03-01

Abstract-Numerous studies have documented the potential for victim-blaming attributions to justify the status quo. Recent work suggests that complementary, victim-enhancing stereotypes may also increase support for existing social arrangements. We seek to reconcile these seemingly contradictory findings by proposing that victim derogation and victim enhancement are alternate routes to system justification, with the preferred route depending on the perception of a causal link between trait and outcome. Derogating "losers" (and lionizing "winners") on traits (e.g., intelligence) that are causally related to outcomes (e.g., wealth vs. poverty) serves to increase system justification, as does compensating "losers" (and downgrading "winners") on traits (e.g., physical attractiveness) that are causally unrelated to those outcomes. We provide converging evidence using system-threat and stereotype-activation paradigms.

Subgenotype A1 of HBV--tracing human migrations in and out of Africa.

Science.gov (United States)

Kramvis, Anna; Paraskevis, Dimitrios

2013-01-01

HBV subgenotype A1 is the dominant genotype A strain in Africa, with molecular characteristics differentiating it from A2, which prevails elsewhere. Outside Africa, A1 is confined to areas with migration history from Africa, including India and Latin America. The aim of this study was to reconstruct A1 phylogeny on a spatial scale in order to determine whether A1 can be used to track human migrations. A phylogenetic comparison of A1 was established using neighbour-joining analysis of complete genomes, and the Bayesian method, implemented in BEAST, was performed on the S region of isolates from 22 countries. Migration events were estimated by ancestral state reconstruction using the criterion of parsimony. From the tree reconstruction, nucleotide divergence calculations and migration analysis, it was evident that Africa was the source of dispersal of A1 globally, and its dispersal to Asia and Latin America occurred at a similar time period. Strains from South Africa were the most divergent, clustering in both the African and Asian/American clades and a South African subclade was the origin of A1. The effect of the 9th to 19th century trade and slave routes on the dispersal of A1 was evident and certain unexpected findings, such as the co-clustering of Somalian and Latin American strains, and the dispersal of A1 from India to Haiti, correlated with historical evidence. Phylogeographic analyses of subgenotype A1 can be used to trace human migrations in and out of Africa and the plausible sites of origin and migration routes are presented.

Can a foreign body migrate against natural body barriers? | Arafat ...

African Journals Online (AJOL)

Pericardial foreign bodies (FBs) are a rare cause of chest pain in children. They can reach the pericardium through several routes including direct or iatrogenic implantation, transbronchial or transesophageal migration of inhaled or swallowed FBs. We reported a case of a 4-year-old girl presenting with persistent chest pain ...

Outward Migration of Giant Planets in Orbital Resonance

Science.gov (United States)

D'Angelo, G.; Marzari, F.

2013-05-01

A pair of giant planets interacting with a gaseous disk may be subject to convergent orbital migration and become locked into a mean motion resonance. If the orbits are close enough, the tidal gaps produced by the planets in the disk may overlap. This represents a necessary condition to activate the outward migration of the pair. However, a number of other conditions must also be realized in order for this mechanism to operate. We have studied how disk properties, such as turbulence viscosity, temperature, surface density gradient, mass, and age, may affect the outcome of the outward migration process. We have also investigated the implications on this mechanism of the planets' gas accretion. If the pair resembles Jupiter and Saturn, the 3:2 orbital resonance may drive them outward until they reach stalling radii for migration, which are within ~10 AU of the star for disks representative of the early proto-solar nebula. However, planet post-formation conditions in the disk indicate that such planets become typically locked in the 1:2 orbital resonance, which does not lead to outward migration. Planet growth via gas accretion tends to alter the planets' mass-ratio and/or the disk accretion rate toward the star, reducing or inhibiting outward migration. Support from NASA Outer Planets Research Program and NASA Origins of Solar Systems Program is gratefully acknowledged.

An Effective Hybrid Routing Algorithm in WSN: Ant Colony Optimization in combination with Hop Count Minimization

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Ailian Jiang

2018-03-01

Full Text Available Low cost, high reliability and easy maintenance are key criteria in the design of routing protocols for wireless sensor networks (WSNs. This paper investigates the existing ant colony optimization (ACO-based WSN routing algorithms and the minimum hop count WSN routing algorithms by reviewing their strengths and weaknesses. We also consider the critical factors of WSNs, such as energy constraint of sensor nodes, network load balancing and dynamic network topology. Then we propose a hybrid routing algorithm that integrates ACO and a minimum hop count scheme. The proposed algorithm is able to find the optimal routing path with minimal total energy consumption and balanced energy consumption on each node. The algorithm has unique superiority in terms of searching for the optimal path, balancing the network load and the network topology maintenance. The WSN model and the proposed algorithm have been implemented using C++. Extensive simulation experimental results have shown that our algorithm outperforms several other WSN routing algorithms on such aspects that include the rate of convergence, the success rate in searching for global optimal solution, and the network lifetime.

Energy Efficiency Performance Improvements for Ant-Based Routing Algorithm in Wireless Sensor Networks

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Adamu Murtala Zungeru

2013-01-01

Full Text Available The main problem for event gathering in wireless sensor networks (WSNs is the restricted communication range for each node. Due to the restricted communication range and high network density, event forwarding in WSNs is very challenging and requires multihop data forwarding. Currently, the energy-efficient ant based routing (EEABR algorithm, based on the ant colony optimization (ACO metaheuristic, is one of the state-of-the-art energy-aware routing protocols. In this paper, we propose three improvements to the EEABR algorithm to further improve its energy efficiency. The improvements to the original EEABR are based on the following: (1 a new scheme to intelligently initialize the routing tables giving priority to neighboring nodes that simultaneously could be the destination, (2 intelligent update of routing tables in case of a node or link failure, and (3 reducing the flooding ability of ants for congestion control. The energy efficiency improvements are significant particularly for dynamic routing environments. Experimental results using the RMASE simulation environment show that the proposed method increases the energy efficiency by up to 9% and 64% in converge-cast and target-tracking scenarios, respectively, over the original EEABR without incurring a significant increase in complexity. The method is also compared and found to also outperform other swarm-based routing protocols such as sensor-driven and cost-aware ant routing (SC and Beesensor.

Spatio-temporal migration patterns of Pacific salmon smolts in rivers and coastal marine waters.

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Michael C Melnychuk

Full Text Available BACKGROUND: Migrations allow animals to find food resources, rearing habitats, or mates, but often impose considerable predation risk. Several behavioural strategies may reduce this risk, including faster travel speed and taking routes with shorter total distance. Descriptions of the natural range of variation in migration strategies among individuals and populations is necessary before the ecological consequences of such variation can be established. METHODOLOGY/PRINCIPAL FINDINGS: Movements of tagged juvenile coho, steelhead, sockeye, and Chinook salmon were quantified using a large-scale acoustic tracking array in southern British Columbia, Canada. Smolts from 13 watersheds (49 watershed/species/year combinations were tagged between 2004-2008 and combined into a mixed-effects model analysis of travel speed. During the downstream migration, steelhead were slower on average than other species, possibly related to freshwater residualization. During the migration through the Strait of Georgia, coho were slower than steelhead and sockeye, likely related to some degree of inshore summer residency. Hatchery-reared smolts were slower than wild smolts during the downstream migration, but after ocean entry, average speeds were similar. In small rivers, downstream travel speed increased with body length, but in the larger Fraser River and during the coastal migration, average speed was independent of body length. Smolts leaving rivers located towards the northern end of the Strait of Georgia ecosystem migrated strictly northwards after ocean entry, but those from rivers towards the southern end displayed split-route migration patterns within populations, with some moving southward. CONCLUSIONS/SIGNIFICANCE: Our results reveal a tremendous diversity of behavioural migration strategies used by juvenile salmon, across species, rearing histories, and habitats, as well as within individual populations. During the downstream migration, factors that had strong

Migration of Tundra Swans (Cygnus columbianus) Wintering in Japan Using Satellite Tracking: Identification of the Eastern Palearctic Flyway.

Science.gov (United States)

Chen, Wenbo; Doko, Tomoko; Fujita, Go; Hijikata, Naoya; Tokita, Ken-Ichi; Uchida, Kiyoshi; Konishi, Kan; Hiraoka, Emiko; Higuchi, Hiroyoshi

2016-02-01

Migration through the Eastern Palearctic (EP) flyway by tundra swans (Cygnus columbianus) has not been thoroughly documented. We satellite-tracked the migration of 16 tundra swans that winter in Japan. The objectives of this study were 1) to show the migration pattern of the EP flyway of tundra swans; 2) to compare this pattern with the migration pattern of whooper swans; and 3) to identify stopover sites that are important for these swans' conservation. Tundra swans were captured at Kutcharo Lake, Hokkaido, in 2009-2012 and satellite-tracked. A new method called the "MATCHED (Migratory Analytical Time Change Easy Detection) method" was developed. Based on median, the spring migration began on 18 April and ended on 27 May. Autumn migration began on 9 September and ended on 2 November. The median duration of the spring and autumn migrations were 48 and 50 days, respectively. The mean duration at one stopover site was 5.5 days and 6.8 days for the spring and autumn migrations, respectively. The number of stopover sites was 3.0 and 2.5 for the spring and autumn migrations, respectively. The mean travel distances for the spring and autumn migrations were 6471 and 6331 km, respectively. Seven migration routes passing Sakhalin, the Amur River, and/or Kamchatka were identified. There were 15, 32, and eight wintering, stopover, and breeding sites, respectively. The migration routes and staging areas of tundra swans partially overlap with those of whooper swans, whose migration patterns have been previously documented. The migration patterns of these two swan species that winter in Japan confirm the importance of the Amur River, Udyl' Lake, Shchastya Bay, Aniva Bay, zaliv Chayvo Lake, zal Piltun Lake, zaliv Baykal Lake, Kolyma River, Buyunda River, Sen-kyuyel' Lake, and northern coastal areas of the Sea of Okhotsk.

On the network convergence process in RPL over IEEE 802.15.4 multihop networks: improvement and trade-offs.

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Kermajani, Hamidreza; Gomez, Carles

2014-07-07

The IPv6 Routing Protocol for Low-power and Lossy Networks (RPL) has been recently developed by the Internet Engineering Task Force (IETF). Given its crucial role in enabling the Internet of Things, a significant amount of research effort has already been devoted to RPL. However, the RPL network convergence process has not yet been investigated in detail. In this paper we study the influence of the main RPL parameters and mechanisms on the network convergence process of this protocol in IEEE 802.15.4 multihop networks. We also propose and evaluate a mechanism that leverages an option available in RPL for accelerating the network convergence process. We carry out extensive simulations for a wide range of conditions, considering different network scenarios in terms of size and density. Results show that network convergence performance depends dramatically on the use and adequate configuration of key RPL parameters and mechanisms. The findings and contributions of this work provide a RPL configuration guideline for network convergence performance tuning, as well as a characterization of the related performance trade-offs.

On the Network Convergence Process in RPL over IEEE 802.15.4 Multihop Networks: Improvement and Trade-Offs

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Hamidreza Kermajani

2014-07-01

Full Text Available The IPv6 Routing Protocol for Low-power and Lossy Networks (RPL has been recently developed by the Internet Engineering Task Force (IETF. Given its crucial role in enabling the Internet of Things, a significant amount of research effort has already been devoted to RPL. However, the RPL network convergence process has not yet been investigated in detail. In this paper we study the influence of the main RPL parameters and mechanisms on the network convergence process of this protocol in IEEE 802.15.4 multihop networks. We also propose and evaluate a mechanism that leverages an option available in RPL for accelerating the network convergence process. We carry out extensive simulations for a wide range of conditions, considering different network scenarios in terms of size and density. Results show that network convergence performance depends dramatically on the use and adequate configuration of key RPL parameters and mechanisms. The findings and contributions of this work provide a RPL configuration guideline for network convergence performance tuning, as well as a characterization of the related performance trade-offs.

First description of autumn migration of Sooty Falcon Falco concolor from the United Arab Emirates to Madagascar using satellite telemetry

Science.gov (United States)

Javed, Sàlim; Douglas, David C.; Khan, Shahid Noor; Nazeer Shah, Junid; Ali Al Hammadi, Abdullah

2012-01-01

The movement and migration pattern of the 'Near Threatened' Sooty Falcon Falco concolor is poorly known. Sooty Falcons breed on the islands of the Arabian Gulf after arriving from their non-breeding areas that are mainly in Madagascar. In the first satellite tracking of the species we fitted a 9.5 g Argos solar powered transmitter on an adult breeding Sooty Falcon off the western coast of Abu Dhabi in the United Arab Emirates. The bird successfully undertook autumn migration to Madagascar, a known wintering area for the species. We document the Sooty Falcon's autumn migration route and stop-over sites. The adult Sooty Falcon initiated its migration at night and with tailwinds, and travelled mainly during daytime hours for 13 days over an inland route of more than 5,656 km. The three stop-over sites in East Africa were characterised by moderate to sparse shrub cover associated with potential sources of water. We discuss the migration pattern of the tracked bird in relation to importance of non-breeding areas for Sooty Falcons and recent declines in numbers in their breeding range.

Global crisis and the Europe-Latin America migration system

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Susana M. Sassone

2014-09-01

Full Text Available This article discusses some of the changes in the connections of the European-Latin American migration system over the past decades. First, we analyse the changing trends and re-routing of the flows between the two ends of the system. Then, we address the complex rearrangements of immigration policies, which in both spaces are again beginning to turn inwards. Lastly, we briefly review the partnerships that are being established between Europe and Latin America via Spain. Within this framework, we wonder whether we are entering a new phase of the globalisation of migration, the dynamic of which is a pendulum with global and regional effects.

Behaviour of stocked and naturally recruited European eels during migration

DEFF Research Database (Denmark)

Westerberg, Håkan; Sjöberg, Niklas; Lagenfelt, Ingvar

2014-01-01

An objection to the stocking of translocated eels as a management measure for the European eel (Anguilla anguilla L.) is that these eels may lack the ability to find their way back to the spawning area in the Sargasso Sea because the translocation will confuse their imprinted navigation. We...... behaviour could be monitored by acoustic tagging, in addition to using archival and satellite tags to track the subsequent marine migration. In the second year, the eels were released on the open coast and only their marine migration was investigated. Eels were tracked more than 2000 km along a route that...

Spring Bird Migration Phenology in Eilat, Israel

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Reuven Yosef

2009-12-01

Full Text Available Analysis of the mean date of first captures and median arrival dates of spring migration for 34 species of birds at Eilat, Israel, revealed that the earlier a species migrates through Eilat, the greater is the inter-annual variation in the total time of its passage. Birds arrive during spring migration in Eilat in four structured and independent waves. The annual fluctuation in the initial arrival dates (initial capture dates and median dates (median date of all captures, not including recaptures, did not depend on the length of the migratory route. This implies that migrants crossing the Sahara desert depart from their winter quarters on different Julian days in different years. We suggest that negative correlations between the median date of the spring migration of early and late migrants depends upon the easterly (Hamsin wind period. Moreover, we believe that the phenology of all birds during spring migration in Eilat is possibly also determined by external factors such as weather conditions on the African continent or global climatic processes in the Northern hemisphere. Orphean Warblers (Sylvia hortensis show a strong positive correlation (rs=-0.502 of initial capture date with calendar years, whereas other species such as Barred Warbler (S. nisoria; rs = -0.391 and Spotted Flycatcher (Muscicapa striata; rs = -0.398 display an insignificant trend. The Dead Sea Sparrow (Passer moabiticus and Red-Backed Shrike (Lanius collurio are positively correlated regarding initial arrival date and medians of spring migration.

INDIVIDUAL BASED MODELLING APPROACH TO THERMAL REFUGE USE BY MIGRATING ADULT SALMON AND STEELHEAD

Science.gov (United States)

Diadromous fish populations in the Pacific Northwest face challenges along their migratory routes from declining habitat quality, harvest, and barriers to longitudinal connectivity. Changes in river temperature regimes are producing an additional challenge for upstream migrating ...

Migrating mule deer: effects of anthropogenically altered landscapes.

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Patrick E Lendrum

Full Text Available Migration is an adaptive strategy that enables animals to enhance resource availability and reduce risk of predation at a broad geographic scale. Ungulate migrations generally occur along traditional routes, many of which have been disrupted by anthropogenic disturbances. Spring migration in ungulates is of particular importance for conservation planning, because it is closely coupled with timing of parturition. The degree to which oil and gas development affects migratory patterns, and whether ungulate migration is sufficiently plastic to compensate for such changes, warrants additional study to better understand this critical conservation issue.We studied timing and synchrony of departure from winter range and arrival to summer range of female mule deer (Odocoileus hemionus in northwestern Colorado, USA, which has one of the largest natural-gas reserves currently under development in North America. We hypothesized that in addition to local weather, plant phenology, and individual life-history characteristics, patterns of spring migration would be modified by disturbances associated with natural-gas extraction. We captured 205 adult female mule deer, equipped them with GPS collars, and observed patterns of spring migration during 2008-2010.Timing of spring migration was related to winter weather (particularly snow depth and access to emerging vegetation, which varied among years, but was highly synchronous across study areas within years. Additionally, timing of migration was influenced by the collective effects of anthropogenic disturbance, rate of travel, distance traveled, and body condition of adult females. Rates of travel were more rapid over shorter migration distances in areas of high natural-gas development resulting in the delayed departure, but early arrival for females migrating in areas with high development compared with less-developed areas. Such shifts in behavior could have consequences for timing of arrival on birthing areas

Prediction Schemes to Enhance the Routing Process in Geographical GPSR Ad Hoc Protocol

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Raed Saqour

2007-01-01

Full Text Available Geographical routing protocols have received a serious attention due to more advantages they have in comparison to the conventional routing protocols. They require information about the physical position of nodes needed to be available. Commonly, each node determines its own position through the use of Global Positioning System (GPS or some other type of positioning service. Greedy Perimeter Stateless Routing (GPSR protocol, which is one of geographical routing protocols, limits the forwarding decision of the packet based on the node's own position, the destination's position and the position of the forwarding node's neighbors. Location information has some inaccuracy depending on the localization system and the environment exists in. This paper aims to study the impact of mobility metrics (beacon interval, and node speed on introducing location information error in GPSR protocol using different mobility models. The effect of these metrics is identified in GPSR as Neighbor Break Link (NBL problem. Based on simulation analysis, mobility prediction schemes are proposed to migrate the observed problem.

Time-domain least-squares migration using the Gaussian beam summation method

Science.gov (United States)

Yang, Jidong; Zhu, Hejun; McMechan, George; Yue, Yubo

2018-04-01

With a finite recording aperture, a limited source spectrum and unbalanced illumination, traditional imaging methods are insufficient to generate satisfactory depth profiles with high resolution and high amplitude fidelity. This is because traditional migration uses the adjoint operator of the forward modeling rather than the inverse operator. We propose a least-squares migration approach based on the time-domain Gaussian beam summation, which helps to balance subsurface illumination and improve image resolution. Based on the Born approximation for the isotropic acoustic wave equation, we derive a linear time-domain Gaussian beam modeling operator, which significantly reduces computational costs in comparison with the spectral method. Then, we formulate the corresponding adjoint Gaussian beam migration, as the gradient of an L2-norm waveform misfit function. An L1-norm regularization is introduced to the inversion to enhance the robustness of least-squares migration, and an approximated diagonal Hessian is used as a preconditioner to speed convergence. Synthetic and field data examples demonstrate that the proposed approach improves imaging resolution and amplitude fidelity in comparison with traditional Gaussian beam migration.

Effect of wind, thermal convection, and variation in flight strategies on the daily rhythm and flight paths of migrating raptors at Georgia's Black Sea coast

NARCIS (Netherlands)

Vansteelant, W.M.G.; Verhelst, B.; Shamoun-Baranes, J.; Bouten, W.; van Loon, E.E.; Bildstein, K.L.

2014-01-01

Every autumn, large numbers of raptors migrate through geographical convergence zones to avoid crossing large bodies of water. At coastal convergence zones, raptors may aggregate along coastlines because of convective or wind conditions. However, the effect of wind and thermal convection on

Migration strategies of Swan Geese Anser cygnoides from northeast Mongolia

Science.gov (United States)

Batbayar, Nyambayar; Takekawa, John Y.; Newman, Scott H.; Prosser, Diann J.; Natsagdorj, Tseveenmyadag; Xiao, Xiangming

2011-01-01

In 2006–2008, 25 Swan Geese Anser cygnoides were marked with solar-powered GPS satellite transmitters in northeast Mongolia to examine the timing and pathways of their migration. Most geese began their autumn migration in August, flying southeast toward a staging area at the Yalu River Estuary on the China-North Korea border. After staging for several weeks, the Swan Geese continued to their wintering grounds at wetlands along the Yangtze River Basin of eastern China in December. Spring migration commenced in late February, and the birds following either a same-route or loop migration to arrive at the breeding grounds in mid April. Swan Geese used a larger number of staging areas for a longer duration when they were north of 42°N latitude; they seemed to avoid staging for extended periods in the highly urbanised areas of eastern China. Further research should examine threats and disturbances to the geese in relation to human population growth and increasing urbanisation.

Nationwide genetic surveillance of Plasmodium vivax in Papua New Guinea reveals heterogeneous transmission dynamics and routes of migration amongst subdivided populations.

Science.gov (United States)

Fola, Abebe A; Nate, Elma; Abby Harrison, G L; Barnadas, Céline; Hetzel, Manuel W; Iga, Jonah; Siba, Peter; Mueller, Ivo; Barry, Alyssa E

2018-03-01

The Asia Pacific Leaders in Malaria Alliance (APLMA) have committed to eliminate malaria from the region by 2030. Papua New Guinea (PNG) has the highest malaria burden in the Asia-Pacific region but with the intensification of control efforts since 2005, transmission has been dramatically reduced and Plasmodium vivax is now the dominant malaria infection in some parts of the country. To gain a better understanding of the transmission dynamics and migration patterns of P. vivax in PNG, here we investigate population structure in eight geographically and ecologically distinct regions of the country. A total of 219 P. vivax isolates (16-30 per population) were successfully haplotyped using 10 microsatellite markers. A wide range of genetic diversity (H e =0.37-0.87, R s =3.60-7.58) and significant multilocus linkage disequilibrium (LD) was observed in six of the eight populations (I A S =0.08-0.15 p-value<0.05) reflecting a spectrum of transmission intensities across the country. Genetic differentiation between regions was evident (Jost's D=0.07-0.72), with increasing divergence of populations with geographic distance. Overall, P. vivax isolates clustered into three major genetic populations subdividing the Mainland lowland and coastal regions, the Islands and the Highlands. P. vivax gene flow follows major human migration routes, and there was higher gene flow amongst Mainland parasite populations than among Island populations. The Central Province (samples collected in villages close to the capital city, Port Moresby), acts as a sink for imported infections from the three major endemic areas. These insights into P. vivax transmission dynamics and population networks will inform targeted strategies to contain malaria infections and to prevent the spread of drug resistance in PNG. Copyright © 2017 Elsevier B.V. All rights reserved.

Trans-equatorial migration routes, staging sites and wintering areas of a high-Arctic avian predator: the long-tailed Skua (Stercorarius longicaudus).

Science.gov (United States)

Gilg, Olivier; Moe, Børge; Hanssen, Sveinn Are; Schmidt, Niels Martin; Sittler, Benoît; Hansen, Jannik; Reneerkens, Jeroen; Sabard, Brigitte; Chastel, Olivier; Moreau, Jérôme; Phillips, Richard A; Oudman, Thomas; Biersma, Elisabeth M; Fenstad, Anette A; Lang, Johannes; Bollache, Loïc

2013-01-01

The Long-tailed Skua, a small (summer, but little is known about its migration and winter distribution. We used light-level geolocators to track the annual movements of eight adult birds breeding in north-east Greenland (n = 3) and Svalbard (n = 5). All birds wintered in the Southern Hemisphere (mean arrival-departure dates on wintering grounds: 24 October-21 March): five along the south-west coast of Africa (0-40°S, 0-15°E), in the productive Benguela upwelling, and three further south (30-40°S, 0-50°E), in an area extending into the south-west Indian Ocean. Different migratory routes and rates of travel were documented during post-breeding (345 km d(-1) in late August-early September) and spring migrations (235 km d(-1) in late April) when most birds used a more westerly flyway. Among the different staging areas, a large region off the Grand Banks of Newfoundland appears to be the most important. It was used in autumn by all but one of the tracked birds (from a few days to three weeks) and in spring by five out of eight birds (from one to more than six weeks). Two other staging sites, off the Iberian coast and near the Azores, were used by two birds in spring for five to six weeks. Over one year, individuals travelled between 43,900 and 54,200 km (36,600-45,700 when excluding staging periods) and went as far as 10,500-13,700 km (mean 12,800 km) from their breeding sites. This study has revealed important marine areas in both the south and north Atlantic Ocean. Sustainable management of these ocean basins will benefit Long-tailed Skuas as well as other trans-equatorial migrants from the Arctic.

A Day-to-Day Route Choice Model Based on Reinforcement Learning

Directory of Open Access Journals (Sweden)

Fangfang Wei

2014-01-01

Full Text Available Day-to-day traffic dynamics are generated by individual traveler’s route choice and route adjustment behaviors, which are appropriate to be researched by using agent-based model and learning theory. In this paper, we propose a day-to-day route choice model based on reinforcement learning and multiagent simulation. Travelers’ memory, learning rate, and experience cognition are taken into account. Then the model is verified and analyzed. Results show that the network flow can converge to user equilibrium (UE if travelers can remember all the travel time they have experienced, but which is not necessarily the case under limited memory; learning rate can strengthen the flow fluctuation, but memory leads to the contrary side; moreover, high learning rate results in the cyclical oscillation during the process of flow evolution. Finally, both the scenarios of link capacity degradation and random link capacity are used to illustrate the model’s applications. Analyses and applications of our model demonstrate the model is reasonable and useful for studying the day-to-day traffic dynamics.

On the numerical simulation of population dynamics with density-dependent migrations and the Allee effects

International Nuclear Information System (INIS)

Sweilam, H N; Khader, M M; Al-Bar, F R

2008-01-01

In this paper, the variational iteration method (VIM) and the Adomian decomposition method (ADM) are presented for the numerical simulation of the population dynamics model with density-dependent migrations and the Allee effects. The convergence of ADM is proved for the model problem. The results obtained by these methods are compared to the exact solution. It is found that these methods are always converges to the right solutions with high accuracy. Furthermore, VIM needs relative less computational work than ADM

An Improved Routing Optimization Algorithm Based on Travelling Salesman Problem for Social Networks

Directory of Open Access Journals (Sweden)

Naixue Xiong

2017-06-01

Full Text Available A social network is a social structure, which is organized by the relationships or interactions between individuals or groups. Humans link the physical network with social network, and the services in the social world are based on data and analysis, which directly influence decision making in the physical network. In this paper, we focus on a routing optimization algorithm, which solves a well-known and popular problem. Ant colony algorithm is proposed to solve this problem effectively, but random selection strategy of the traditional algorithm causes evolution speed to be slow. Meanwhile, positive feedback and distributed computing model make the algorithm quickly converge. Therefore, how to improve convergence speed and search ability of algorithm is the focus of the current research. The paper proposes the improved scheme. Considering the difficulty about searching for next better city, new parameters are introduced to improve probability of selection, and delay convergence speed of algorithm. To avoid the shortest path being submerged, and improve sensitive speed of finding the shortest path, it updates pheromone regulation formula. The results show that the improved algorithm can effectively improve convergence speed and search ability for achieving higher accuracy and optimal results.

Migration waves to the Baltic Sea region.

Science.gov (United States)

Lappalainen, T; Laitinen, V; Salmela, E; Andersen, P; Huoponen, K; Savontaus, M-L; Lahermo, P

2008-05-01

In this study, the population history of the Baltic Sea region, known to be affected by a variety of migrations and genetic barriers, was analyzed using both mitochondrial DNA and Y-chromosomal data. Over 1200 samples from Finland, Sweden, Karelia, Estonia, Setoland, Latvia and Lithuania were genotyped for 18 Y-chromosomal biallelic polymorphisms and 9 STRs, in addition to analyzing 17 coding region polymorphisms and the HVS1 region from the mtDNA. It was shown that the populations surrounding the Baltic Sea are genetically similar, which suggests that it has been an important route not only for cultural transmission but also for population migration. However, many of the migrations affecting the area from Central Europe, the Volga-Ural region and from Slavic populations have had a quantitatively different impact on the populations, and, furthermore, the effects of genetic drift have increased the differences between populations especially in the north. The possible explanations for the high frequencies of several haplogroups with an origin in the Iberian refugia (H1, U5b, I1a) are also discussed.

ANALYSIS OF CONVERGENCE WITHIN THE EUROPEAN UNION SIGMA AND BETA CONVERGENCE

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Begu Liviu-Stelian

2010-12-01

Full Text Available Real convergence study began with the development of neoclassical models of growth and especially with the passage of econometric applications of these models. In this paper we present applications of indicators and patterns of convergence on the example of European Union member countries and some current economic impact assessments on European convergence process. This analysis is based on the estimated a- and b convergence and on Markov chains. The study deals with the economic convergence of the European countries and especially the convergence of the EU countries, including Romania. In the end of the study presents several economic scenarios for a faster and easier exit from the current crisis in Romania.

Mediterranean Migrations: Regionalisms Versus Globalisation

Directory of Open Access Journals (Sweden)

Martin Baldwin-Eduards

2004-06-01

Full Text Available This paper challenges the claim of globalisation as a cause ofimmigration into Southern Europe and, on an empirical basis, identifies regionalisation as being the primary issue, along with networked migratory patterns. However, the changing patterns of immigration do present challenges to both state and society. It is argued here that recent policy responses in Portugal, Italy and Spain have been inconsistent and irrational – reflecting more the ‘securitisation’ of migration than European reality. Earlier policy innovations are identified, by country and date: most of these have now been abandoned. It is suggested that all of Southern Europe has converged onto a statist, restrictionist model of immigration control that was formerly held only by Greece. The principal characteristics of this model are outlined, along with a migration flowchart and indicative data for migrant flows and sub-flows in Italy and Spain. In the final section, I try to show that the needs of the economy cannot be predicted, immigration cannot becontrolled in the manner currently being enforced across Southern Europe, and attempts to do so will damage rather than improve economic productivity and growth. The concept of an accomodating immigration policy is advanced, whereby the state tries to manage the needs of both employers and potential migrants. Six guidelines for policy development are suggested – most of which have alreadybeen successfully carried out in the European Union. These are the following: migration in order to find a job; circular cross-border migration; EU level negotiation of readmission agreements; the need for a variety of migration-for-employment schemes; legal residence should not depend upon continuity of employment; and discreet legalisation will still be needed in Southern Europe.

Wind conditions and geography shape the first outbound migration of juvenile honey buzzards and their distribution across sub-Saharan Africa.

Science.gov (United States)

Vansteelant, W M G; Kekkonen, J; Byholm, P

2017-05-31

Contemporary tracking studies reveal that low migratory connectivity between breeding and non-breeding ranges is common in migrant landbirds. It is unclear, however, how internal factors and early-life experiences of individual migrants shape the development of their migration routes and concomitant population-level non-breeding distributions. Stochastic wind conditions and geography may determine whether and where migrants end up by the end of their journey. We tested this hypothesis by satellite-tagging 31 fledgling honey buzzards Pernis apivorus from southern Finland and used a global atmospheric reanalysis model to estimate the wind conditions they encountered on their first outbound migration. Migration routes diverged rapidly upon departure and the birds eventually spread out across 3340 km of longitude. Using linear regression models, we show that the birds' longitudinal speeds were strongly affected by zonal wind speed, and negatively affected by latitudinal wind, with significant but minor differences between individuals. Eventually, 49% of variability in the birds' total longitudinal displacements was accounted for by wind conditions on migration. Some birds circumvented the Baltic Sea via Scandinavia or engaged in unusual downwind movements over the Mediterranean, which also affected the longitude at which these individuals arrived in sub-Saharan Africa. To understand why adult migrants use the migration routes and non-breeding sites they use, we must take into account the way in which wind conditions moulded their very first journeys. Our results present some of the first evidence into the mechanisms through which low migratory connectivity emerges. © 2017 The Authors.

Wind conditions and geography shape the first outbound migration of juvenile honey buzzards and their distribution across sub-Saharan Africa

Science.gov (United States)

Kekkonen, J.; Byholm, P.

2017-01-01

Contemporary tracking studies reveal that low migratory connectivity between breeding and non-breeding ranges is common in migrant landbirds. It is unclear, however, how internal factors and early-life experiences of individual migrants shape the development of their migration routes and concomitant population-level non-breeding distributions. Stochastic wind conditions and geography may determine whether and where migrants end up by the end of their journey. We tested this hypothesis by satellite-tagging 31 fledgling honey buzzards Pernis apivorus from southern Finland and used a global atmospheric reanalysis model to estimate the wind conditions they encountered on their first outbound migration. Migration routes diverged rapidly upon departure and the birds eventually spread out across 3340 km of longitude. Using linear regression models, we show that the birds' longitudinal speeds were strongly affected by zonal wind speed, and negatively affected by latitudinal wind, with significant but minor differences between individuals. Eventually, 49% of variability in the birds' total longitudinal displacements was accounted for by wind conditions on migration. Some birds circumvented the Baltic Sea via Scandinavia or engaged in unusual downwind movements over the Mediterranean, which also affected the longitude at which these individuals arrived in sub-Saharan Africa. To understand why adult migrants use the migration routes and non-breeding sites they use, we must take into account the way in which wind conditions moulded their very first journeys. Our results present some of the first evidence into the mechanisms through which low migratory connectivity emerges. PMID:28539514

The differential role of social networks. Strategies and routes in Brazilian migration to Portugal and the Netherlands

NARCIS (Netherlands)

M.J. van Meeteren (Masja); S. Pereira (Sonia)

2013-01-01

textabstractAbstract This paper draws on qualitative and quantitative data on the migration experiences of Brazilians living in Portugal and the Netherlands to reflect and expand upon the existing knowledge on the role of social networks in migration processes. We consider different migrant profiles

Science and technology convergence: with emphasis for nanotechnology-inspired convergence

Energy Technology Data Exchange (ETDEWEB)

Bainbridge, William S.; Roco, Mihail C., E-mail: mroco@nsf.gov [National Science Foundation (United States)

2016-07-15

Convergence offers a new universe of discovery, innovation, and application opportunities through specific theories, principles, and methods to be implemented in research, education, production, and other societal activities. Using a holistic approach with shared goals, convergence seeks to transcend existing human limitations to achieve improved conditions for work, learning, aging, physical, and cognitive wellness. This paper outlines ten key theories that offer complementary perspectives on this complex dynamic. Principles and methods are proposed to facilitate and enhance science and technology convergence. Several convergence success stories in the first part of the 21st century—including nanotechnology and other emerging technologies—are discussed in parallel with case studies focused on the future. The formulation of relevant theories, principles, and methods aims at establishing the convergence science.

Science and technology convergence: with emphasis for nanotechnology-inspired convergence

International Nuclear Information System (INIS)

Bainbridge, William S.; Roco, Mihail C.

2016-01-01

Convergence offers a new universe of discovery, innovation, and application opportunities through specific theories, principles, and methods to be implemented in research, education, production, and other societal activities. Using a holistic approach with shared goals, convergence seeks to transcend existing human limitations to achieve improved conditions for work, learning, aging, physical, and cognitive wellness. This paper outlines ten key theories that offer complementary perspectives on this complex dynamic. Principles and methods are proposed to facilitate and enhance science and technology convergence. Several convergence success stories in the first part of the 21st century—including nanotechnology and other emerging technologies—are discussed in parallel with case studies focused on the future. The formulation of relevant theories, principles, and methods aims at establishing the convergence science.

Predicted impact of barriers to migration on the Serengeti wildebeest population.

Directory of Open Access Journals (Sweden)

Ricardo M Holdo

Full Text Available The Serengeti wildebeest migration is a rare and spectacular example of a once-common biological phenomenon. A proposed road project threatens to bisect the Serengeti ecosystem and its integrity. The precautionary principle dictates that we consider the possible consequences of a road completely disrupting the migration. We used an existing spatially-explicit simulation model of wildebeest movement and population dynamics to explore how placing a barrier to migration across the proposed route (thus creating two disjoint but mobile subpopulations might affect the long-term size of the wildebeest population. Our simulation results suggest that a barrier to migration--even without causing habitat loss--could cause the wildebeest population to decline by about a third. The driver of this decline is the effect of habitat fragmentation (even without habitat loss on the ability of wildebeest to effectively track temporal shifts in high-quality forage resources across the landscape. Given the important role of the wildebeest migration for a number of key ecological processes, these findings have potentially important ramifications for ecosystem biodiversity, structure, and function in the Serengeti.

Landbird migration in the American West: Recent progress and future research directions

Science.gov (United States)

Carlisle, J.D.; Skagen, S.K.; Kus, B.E.; van Riper, Charles; Paxton, K.L.; Kelly, J.F.

2009-01-01

Our knowledge of avian behaviors during the nonbreeding period still lags behind that of the breeding season, but the last decade has witnessed a proliferation in research that has yielded significant progress in understanding migration patterns of North American birds. And, although historically the great majority of migration research has been conducted in the eastern half of the continent, there has been much recent progress on aspects of avian migration in the West. In particular, expanded use of techniques such as radar, plasma metabolites, mist-netting, count surveys, stable isotopes, genetic data, and animal tracking, coupled with an increase in multi-investigator collaborations, have all contributed to this growth of knowledge. There is increasing recognition that migration is likely the most limiting time of year for migratory birds, increasing the importance of continuing to decipher patterns of stopover ecology, identifying critical stopover habitats, and documenting migration routes in the diverse and changing landscapes of the American West. Here, we review and briefly synthesize the latest findings and advances in avian migration and consider research needs to guide future research on migration in the West. ?? 2009 by The Cooper Ornithological Society. All rights reserved.

IT-BT convergence technology

International Nuclear Information System (INIS)

2012-12-01

This book explains IT-BT convergence technology as the future technology, which includes a prolog, easy IT-BT convergence technology that has infinite potentials for new value, policy of IT-BT convergence technology showing the potential of smart Korea, IT-BT convergence opening happy future, for the new future of IT powerful nation Korea with IT-BT convergence technology and an epilogue. This book reveals the conception, policy, performance and future of IT-BT convergence technology.

Intermingling and seasonal migrations of Greenland halibut ( Reinhardtius hippoglossoides ) populations determined from tagging studies

DEFF Research Database (Denmark)

Boje, Jesper

2002-01-01

A total of 7244 Greenland halibut (Reinhardtius hippoglossoides' Walbaum) were tagged in Greenland waters between 1986 and 1998 to increase information on stock delineations, to clarify migration routes, and to describe the seasonal movements of cord populations. At present 517 recaptured Greenla...

Differential regulation of microtubule severing by APC underlies distinct patterns of projection neuron and interneuron migration

Science.gov (United States)

Eom, Tae-Yeon; Stanco, Amelia; Guo, Jiami; Wilkins, Gary; Deslauriers, Danielle; Yan, Jessica; Monckton, Chase; Blair, Josh; Oon, Eesim; Perez, Abby; Salas, Eduardo; Oh, Adrianna; Ghukasyan, Vladimir; Snider, William D.; Rubenstein, John L. R.; Anton, E. S.

2014-01-01

Coordinated migration of distinct classes of neurons to appropriate positions leads to the formation of functional neuronal circuitry in the cerebral cortex. Two major classes of cortical neurons, interneurons and projection neurons, utilize distinctly different modes (radial vs. tangential) and routes of migration to arrive at their final positions in the cerebral cortex. Here, we show that adenomatous polyposis coli (APC) modulates microtubule (MT) severing in interneurons to facilitate tangential mode of interneuron migration, but not the glial-guided, radial migration of projection neurons. APC regulates the stability and activity of the MT severing protein p60-katanin in interneurons to promote the rapid remodeling of neuronal processes necessary for interneuron migration. These findings reveal how severing and restructuring of MTs facilitate distinct modes of neuronal migration necessary for laminar organization of neurons in the developing cerebral cortex. PMID:25535916

The migration of 111Indium-labelled polymorphonuclear leucocytes into the oral cavity in the rhesus monkey

International Nuclear Information System (INIS)

Scully, C.; Challacombe, S.J.

1979-01-01

The route of migration of polymorphonuclear leucocytes (PMNL) from blood to the oral cavity was examined in rhesus monkeys. PMNL were isolated from the peripheral blood of eleven rhesus monkeys by dextran sedimentation, radiolabelled with 111 Indium and administered intravenously. Sequential samples of crevicular fluid washings (CFW), mixed and parotid saliva and mucosal washings were taken after injection of the labelled PMNL and harvested on glass fibre discs. Highest numbers of labelled PMNL were detected in CFW. CEll-associated radioactivity was detected in CFW within 20 min of injection of labelled PMNL and reached a maximal level 1 hour after injection. PMNL were found in CFW from monkeys with clinically normal gingiva but the number of labelled PMNL in CFW increased with increasing gingival index. Significant number of PMNL migrated into mixed saliva within 30 min, and low numbers of PMNL were detected in mucosal washings and in parotid saliva after 30 min. The results indicate that the migration time of the PMNL from blood to the oral cavity is less than 30 min, irrespective of the gingival index, that the gingival crevice is the main route of entry of PMNL to the oral cavity and that the numbers of PMNL migrating to the crevice increase as the gingival index rises. (author)

An Immune Cooperative Particle Swarm Optimization Algorithm for Fault-Tolerant Routing Optimization in Heterogeneous Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Yifan Hu

2012-01-01

Full Text Available The fault-tolerant routing problem is important consideration in the design of heterogeneous wireless sensor networks (H-WSNs applications, and has recently been attracting growing research interests. In order to maintain k disjoint communication paths from source sensors to the macronodes, we present a hybrid routing scheme and model, in which multiple paths are calculated and maintained in advance, and alternate paths are created once the previous routing is broken. Then, we propose an immune cooperative particle swarm optimization algorithm (ICPSOA in the model to provide the fast routing recovery and reconstruct the network topology for path failure in H-WSNs. In the ICPSOA, mutation direction of the particle is determined by multi-swarm evolution equation, and its diversity is improved by immune mechanism, which can enhance the capacity of global search and improve the converging rate of the algorithm. Then we validate this theoretical model with simulation results. The results indicate that the ICPSOA-based fault-tolerant routing protocol outperforms several other protocols due to its capability of fast routing recovery mechanism, reliable communications, and prolonging the lifetime of WSNs.

Interdependence of macrophage migration and ventral nerve cord development in Drosophila embryos.

Science.gov (United States)

Evans, Iwan R; Hu, Nan; Skaer, Helen; Wood, Will

2010-05-01

During embryonic development, Drosophila macrophages (haemocytes) undergo a series of stereotypical migrations to disperse throughout the embryo. One major migratory route is along the ventral nerve cord (VNC), where haemocytes are required for the correct development of this tissue. We show, for the first time, that a reciprocal relationship exists between haemocytes and the VNC and that defects in nerve cord development prevent haemocyte migration along this structure. Using live imaging, we demonstrate that the axonal guidance cue Slit and its receptor Robo are both required for haemocyte migration, but signalling is not autonomously required in haemocytes. We show that the failure of haemocyte migration along the VNC in slit mutants is not due to a lack of chemotactic signals within this structure, but rather to a failure in its detachment from the overlying epithelium, creating a physical barrier to haemocyte migration. This block of haemocyte migration in turn disrupts the formation of the dorsoventral channels within the VNC, further highlighting the importance of haemocyte migration for correct neural development. This study illustrates the important role played by the three-dimensional environment in directing cell migration in vivo and reveals an intriguing interplay between the developing nervous system and the blood cells within the fly, demonstrating that their development is both closely coupled and interdependent.

GROWING REGIONAL SCIENTIFIC MIGRATION AND MOBILITY: THE EUROPEAN UNION AND THE EASTERN PARTNERSHIP

Directory of Open Access Journals (Sweden)

Ganna KHARLAMOVA

2016-11-01

Full Text Available The article contributes to the growing strand of the literature on the scientific mobility and migration in the European Union (EU and the Eastern Partnership. The paper provides the quantitative assessment of the costs and benefits of ‘smart’ labour migration in the Eastern Partnership (EaP countries (particularly, Ukraine, explores the potential of future new rules for the mobility within the EU-EaP, and proposes some policy recommendations to enhance the benefits stemming from such flows. One of the rigorous idea – to provide an explanation whether the scientific migration and mobility, and remittances impact on economic development in the donor and recipient states, and, in particular, how important it is as a resource for the EaP enhancing. The convergence effect of scientific migration in the EU and the Eastern Partnership region is considered by means of calculative assessment.

Convergence in Multispecies Interactions

OpenAIRE

Bittleston, Leonora Sophia; Pierce, Naomi E.; Ellison, Aaron M.; Pringle, Anne

2016-01-01

The concepts of convergent evolution and community convergence highlight how selective pressures can shape unrelated organisms or communities in similar ways. We propose a related concept, convergent interactions, to describe the independent evolution of multispecies interactions with similar physiological or ecological functions. A focus on convergent interactions clarifies how natural selection repeatedly favors particular kinds of associations among species. Characterizing convergent inter...

Migration and winter distribution of the Chestnutcollared Longspur

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Ellison Kevin

2017-12-01

Full Text Available The Chestnut-collared Longspur (Calcarius ornatus is one of five grassland songbirds, endemic within North America, with populations that have declined >65% since the 1960s. These species breed and winter in the northern and southern Great Plains, respectively. Identifying migration routes, wintering sites, and the timing of their habitat use is key for understanding the relative magnitude of threats across the annual cycle and effectively targeting habitats for conservation. We tracked migratory movements of seven Chestnut-collared Longspurs with light-level geolocators deployed in Canada. Individuals wintered up to 112-1,200km apart. All followed the Central Flyway, circumvented high-elevation terrain, and traveled east of the breeding location. Unlike most songbirds, the durations of spring and fall migrations were similar; on average 42 ± 7d and 41 ± 5d during fall and spring migrations, respectively, for an approximately 2,000km migration; this highlights the need to better understand habitat requirements during migration for grassland songbirds. Using geospatial habitat data, we assessed winter distribution overlap with four other endemic grassland songbirds; wintering range overlapped 63-99%. Future studies should use more precise devices (e.g., archival GPS units, programmed for data collection dates from this study, to identify specific migratory sites for better conserving this and associated grassland species.

Migration history of air-breathing fishes reveals Neogene atmospheric circulation patterns

Science.gov (United States)

Böhme, M.

2004-05-01

The migration history of an air-breathing fish group (Channidae; snakehead fishes) is used for reconstructing Neogene Eurasian precipitation and atmospheric circulation patterns. The study shows that snakeheads are sensitive indicators of summer precipitation maxima in subtropical and temperate regions, and are present regularly if the wettest month exceeds 150 mm precipitation and 20 °C mean temperature. The analysis of 515 fossil freshwater fish deposits of the past 50 m.y. from Africa and Eurasia shows two continental-scale migration events from the snakeheads' center of origin in the south Himalayan region, events that can be related to changes in the Northern Hemisphere circulation pattern. The first migration, ca. 17.5 Ma, into western and central Eurasia may have been caused by a northward shift of the Intertropical Convergence Zone that brought western Eurasia under the influence of trade winds that produced a zonal and meridional precipitation gradient in Europe. During the second migration, between 8 and 4 Ma, into Africa and East Asia, snakeheads reached their present-day distribution. This migration could have been related to the intensification of the Asian monsoon that brought summer precipitation to their migratory pathways in East Africa Arabia and East Asia.

Convergent microRNA actions coordinate neocortical development.

Science.gov (United States)

Barca-Mayo, Olga; De Pietri Tonelli, Davide

2014-08-01

Neocortical development is a complex process that, at the cellular level, involves tight control of self-renewal, cell fate commitment, survival, differentiation and delamination/migration. These processes require, at the molecular level, the precise regulation of intrinsic signaling pathways and extrinsic factors with coordinated action in a spatially and temporally specific manner. Transcriptional regulation plays an important role during corticogenesis; however, microRNAs (miRNAs) are emerging as important post-transcriptional regulators of various aspects of central nervous system development. miRNAs are a class of small, single-stranded noncoding RNA molecules that control the expression of the majority of protein coding genes (i.e., targets). How do different miRNAs achieve precise control of gene networks during neocortical development? Here, we critically review all the miRNA-target interactions validated in vivo, with relevance to the generation and migration of pyramidal-projection glutamatergic neurons, and for the initial formation of cortical layers in the embryonic development of rodent neocortex. In particular, we focus on convergent miRNA actions, which are still a poorly understood layer of complexity in miRNA signaling, but potentially one of the keys to disclosing how miRNAs achieve the precise coordination of complex biological processes such as neocortical development.

On the convergence of finite state mean-field games through Γ-convergence

KAUST Repository

Ferreira, Rita C.; Gomes, Diogo A.

2014-01-01

In this study, we consider the long-term convergence (trend toward an equilibrium) of finite state mean-field games using Γ-convergence. Our techniques are based on the observation that an important class of mean-field games can be viewed as the Euler-Lagrange equation of a suitable functional. Therefore, using a scaling argument, one can convert a long-term convergence problem into a Γ-convergence problem. Our results generalize previous results related to long-term convergence for finite state problems. © 2014 Elsevier Inc.

On the convergence of finite state mean-field games through Γ-convergence

KAUST Repository

Ferreira, Rita C.

2014-10-01

In this study, we consider the long-term convergence (trend toward an equilibrium) of finite state mean-field games using Γ-convergence. Our techniques are based on the observation that an important class of mean-field games can be viewed as the Euler-Lagrange equation of a suitable functional. Therefore, using a scaling argument, one can convert a long-term convergence problem into a Γ-convergence problem. Our results generalize previous results related to long-term convergence for finite state problems. © 2014 Elsevier Inc.

Network Convergence

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Network Convergence. User is interested in application and content - not technical means of distribution. Boundaries between distribution channels fade out. Network convergence leads to seamless application and content solutions.

A network society, social media, migration and mission

Directory of Open Access Journals (Sweden)

Niemandt, Cornelius J. P. (Nelus

2013-05-01

Full Text Available Human mobility and migration are closely associated with and reciprocally influenced by globalisation. Add the relentless connectivity facilitated by the proliferation of mobile communication and the emergence of social media to this mixture, and an emerging new glocal culture is evident. People are not only migrating to new localities and territories, but simultaneously into a new culture. We are witnessing the greatest mass migration in the history of humanity from the real to the virtual world. It is a shift from shared space to shared interest. The metaphor of a river in flood has been used to describe the fact that migrant communities are a point of convergence of some of the biggest challenges facing the church and society at large: globalisation, hyperdiversity, interconnectedness, a Google culture and postmodern tribalism. Culture flows like a river and the church functions as a bridge connecting humans striving to make sense of life and Scripture as well as the tradition transmitted over the centuries. Some of the missional challenges will be to incarnate the gospel in this emerging culture. This study was positioned at the convergence of two important processes the rise of the network society (especially social media and migration. It took up two of the challenges posed at Edinburgh 2010, namely to fruitfully integrate the role of media in modern society into overall missiological thinking, and to think about the call for a structural reform of the church to grapple with the challenges of migration. The network society represents a profound social transformation. New technologies deliver connectedness in the palms of our hands and social media serve as an expression of the passion for connection, community and knowing others and being known by others. This research is a theoretical and missiological reflection on the role and importance of social media such as Facebook in migrant communities. It investigated issues such as

Migration strategy affects avian influenza dynamics in mallards (Anas platyrhynchos).

Science.gov (United States)

Takekawa, John Y.; Hill, Nichola J.; Ackerman, Joshua T.; Herring, Garth; Hobson, Keith; Cardona, Carol J.; Runstadler, Jonathan; Boyce, Walter M.

2012-01-01

Studies of pathogen transmission typically overlook that wildlife hosts can include both migrant and resident populations when attempting to model circulation. Through the application of stable isotopes in flight feathers, we estimated the migration strategy of mallards (Anas platyrhynchos) occurring on California wintering grounds. Our study demonstrates that mallards- a principal host of avian influenza virus (AIV) in nature, contribute differently to virus gene flow depending on migration strategy. No difference in AIV prevalence was detected between resident (9.6%), intermediate-distance (9.6%) and long-distance migrants (7.4%). Viral diversity among the three groups was also comparable, possibly owing to viral pool mixing when birds converge at wetlands during winter. However, migrants and residents contributed differently to the virus gene pool at wintering wetlands. Migrants introduced virus from northern breeding grounds (Alaska and the NW Pacific Rim) into the wintering population, facilitating gene flow at continental scales, but circulation of imported virus appeared to be limited. In contrast, resident mallards acted as AIV reservoirs facilitating year-round circulation of limited subtypes (i.e. H5N2) at lower latitudes. This study supports a model of virus exchange in temperate regions driven by the convergence of wild birds with separate geographic origins and exposure histories.

Local ecological knowledge of fishers about the life cycle and temporal patterns in the migration of mullet (Mugil liza in Southern Brazil

Directory of Open Access Journals (Sweden)

Dannieli Firme Herbst

Full Text Available This research investigates local ecological knowledge of fishers in communities along a latitudinal gradient in the coast of the Santa Catarina State, regarding the life cycle of mullets Mugil liza (migration, feeding, and reproductive behavior. Our sampling encompassed eight Santa Catarina coastal cities (nine artisanal fishing sites and engaged 45 key informants (28- 86 years of age through semi-structured interviews from August/2011 to March/2012. This fish species feeds and grows in lagoon and estuarine systems, migrating to the sea for reproduction, and spawning. Fishers acknowledged the Patos Lagoon and the Plata River as the main source of mullet schools. Migration occurs from South to North and the routes vary according to climatic and oceanographic conditions (e.g., low temperatures, south winds, rainfall, currents, salinity. These conditions influence the abundance of mullets (and therefore fisheries success, their migration and stops in locations such as beaches, rocky shores, and islands. According to fishers, mullet spawning occurs throughout the coast of the Santa Catarina State and they feed in lagoons and riverine systems but also out at sea during migration. In conclusion, fishers possess a detailed knowledge about mullet life cycle and they identify intra and interannual variations in migration routes, a pattern that should be considered in managing the fishery.

The Great Migration and African-American Genomic Diversity.

Directory of Open Access Journals (Sweden)

Soheil Baharian

2016-05-01

Full Text Available We present a comprehensive assessment of genomic diversity in the African-American population by studying three genotyped cohorts comprising 3,726 African-Americans from across the United States that provide a representative description of the population across all US states and socioeconomic status. An estimated 82.1% of ancestors to African-Americans lived in Africa prior to the advent of transatlantic travel, 16.7% in Europe, and 1.2% in the Americas, with increased African ancestry in the southern United States compared to the North and West. Combining demographic models of ancestry and those of relatedness suggests that admixture occurred predominantly in the South prior to the Civil War and that ancestry-biased migration is responsible for regional differences in ancestry. We find that recent migrations also caused a strong increase in genetic relatedness among geographically distant African-Americans. Long-range relatedness among African-Americans and between African-Americans and European-Americans thus track north- and west-bound migration routes followed during the Great Migration of the twentieth century. By contrast, short-range relatedness patterns suggest comparable mobility of ∼15-16km per generation for African-Americans and European-Americans, as estimated using a novel analytical model of isolation-by-distance.

Two Chaotic Patterns of Dynamic Risk Definition for Solving Hazardous Materials Routing Problem

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Abbas Mahmoudabadi

2015-01-01

Full Text Available In the case of determining routes for hazardous material transportation, risk is considered as a main attribute. Transport risk, which is usually combined with other attributes such as cost or travel time, plays a significant role in determining paths for hazardous materials transportation. Since, risk is chaotically affected by road incidents, decision makers are dealing with selecting a method for defining chaotic risk factors in hazmat transportation. In this paper, transport risk has been defined as a chaotic variable using two different methods of generating chaotic patterns. In an experimental road network, which consists of eighty-nine nodes and one hundred and one two-way links, two different methods of generating chaotic variables have been used for applying the proposed procedure. In addition, results for different amounts of risk and cost have also been analyzed in case study. Results revealed that different cost and risk priorities change the frequencies of selected paths determined for hazmat transportation, but the route convergence of the route to chaos method is better than that of the logistic map equation.

Distribution and migration chronology of Eastern population sandhill cranes

Science.gov (United States)

Fronczak, David L.; Andersen, David; Hanna, Everett E.; Cooper, Thomas R.

2017-01-01

The Eastern Population (EP) of greater sandhill cranes (Antigone canadensis tabida; cranes) is expanding in size and geographic range. Little information exists regarding the geographic extent of breeding, migration, and wintering ranges, migration chronology, or use of staging areas for cranes in the EP. To obtain these data, we attached solar global positioning system (GPS) platform transmitting terminals (PTTs) to 42 sandhill cranes and monitored daily locations from December 2009 through August 2014. On average, tagged cranes settled in summer areas during late‐March in Minnesota (7%), Wisconsin (29%), Michigan, USA (21%), and Ontario, Canada (38%) and arrived at their winter terminus beginning mid‐December in Indiana (15%), Kentucky (3%), Tennessee (45%), Georgia (5%), and Florida (32%). Cranes initiated spring migration beginning mid‐February to their respective summer areas on routes similar to those used during fall migration. Twenty‐five marked cranes returned to the same summer area after a second spring migration, of which 19 (76%) settled cranes in the EP, we estimated that approximately 29–31% of cranes that summered in both Wisconsin and the Lower Peninsula of Michigan were not in areas included in the survey. The information we collected on crane movements provides insight into distribution and migration chronology that will aid in assessment of the current USFWS fall survey. In addition, information on specific use sites can assist state and federal managers to identify and protect key staging and winter areas particularly during current and future recreational harvest seasons.

Migration of northern yellowstone elk: Implications of spatial structuring

Science.gov (United States)

White, P.J.; Proffitt, K.M.; Mech, L.D.; Evans, S.B.; Cunningham, J.A.; Hamlin, K.L.

2010-01-01

Migration can enhance survival and recruitment of mammals by increasing access to higher-quality forage or reducing predation risk, or both. We used telemetry locations collected from 140 adult female elk during 20002003 and 20072008 to identify factors influencing the migration of northern Yellowstone elk. Elk wintered in 2 semidistinct herd segments and migrated 10140 km to at least 12 summer areas in Yellowstone National Park (YNP) and nearby areas of Montana. Spring migrations were delayed after winters with increased snow pack, with earlier migration in years with earlier vegetation green-up. Elk wintering at lower elevations outside YNP migrated an average of 13 days earlier than elk at higher elevations. The timing of autumn migrations varied annually, but elk left their summer ranges at about the same time regardless of elevation, wolf numbers, or distance to their wintering areas. Elk monitored for multiple years typically returned to the same summer (96 fidelity, n 52) and winter (61 fidelity, n 41) ranges. Elk that wintered at lower elevations in or near the northwestern portion of the park tended to summer in the western part of YNP (56), and elk that wintered at higher elevations spent summer primarily in the eastern and northern parts of the park (82). Elk did not grossly modify their migration timing, routes, or use areas after wolf restoration. Elk mortality was low during summer and migration (8 of 225 elk-summers). However, spatial segregation and differential mortality and recruitment between herd segments on the northern winter range apparently contributed to a higher proportion of the elk population wintering outside the northwestern portion of YNP and summering in the western portion of the park. This change could shift wolf spatial dynamics more outside YNP and increase the risk of transmission of brucellosis from elk to cattle north of the park. ?? 2010 American Society of Mammalogists.

Local Convergence and Radius of Convergence for Modified Newton Method

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Măruşter Ştefan

2017-12-01

Full Text Available We investigate the local convergence of modified Newton method, i.e., the classical Newton method in which the derivative is periodically re-evaluated. Based on the convergence properties of Picard iteration for demicontractive mappings, we give an algorithm to estimate the local radius of convergence for considered method. Numerical experiments show that the proposed algorithm gives estimated radii which are very close to or even equal with the best ones.

Field-scale colloid migration experiments in a granite fracture

International Nuclear Information System (INIS)

Vilks, P.; Frost, L.H.; Bachinski, D.B.

1997-01-01

An understanding of particle migration in fractured rock, required to assess the potential for colloid-facilitated transport of radionuclides, can best be evaluated when the results of laboratory experiments are demonstrated in the field. Field-scale migration experiments with silica colloids were carried out at AECL's Underground Research Laboratory (URL), located in southern Manitoba, to develop the methodology for large-scale migration experiments and to determine whether colloid transport is possible over distances up to 17 m. In addition, these experiments were designed to evaluate the effects of flow rate and flow path geometry, and to determine whether colloid tracers could be used to provide additional information on subsurface transport to that provided by conservative tracers alone. The colloid migration studies were carried out as part of AECL's Transport Properties in Highly Fractured Rock Experiment, the objective of which was to develop and demonstrate methods for evaluating the solute transport characteristics of zones of highly fractured rock. The experiments were carried out within fracture zone 2 as two-well recirculating, two-well non-recirculating, and convergent flow tests, using injection rates of 5 and 101 min -1 . Silica colloids with a 20 nm size were used because they are potentially mobile due to their stability, small size and negative surface charge. The shapes of elution profiles for colloids and conservative tracers were similar, demonstrating that colloids can migrate over distances of 17 m. The local region of drawdown towards the URL shaft affected colloid migration and, to a lesser extent, conservative tracer migration within the flow field established by the two-well tracer tests. These results indicate that stable colloids, with sizes as small as 20 nm, have different migration properties from dissolved conservative tracers. (author)

Decoupled deblurring filter and its application to elastic migration and inversion

KAUST Repository

Feng, Zongcai

2017-08-17

We present a decoupled deblurring filter that approximates the multiparameter Hessian inverse by using local filters to approximate its submatrices for the same and different parameter classes. Numerical tests show that the filter not only reduces the footprint noise, balances the amplitudes and increases the resolution of the elastic migration images, but also mitigates the crosstalk artifacts. When used as a preconditioner, it accelerates the convergence rate for elastic inversion.

Inferring the rules of social interaction in migrating caribou.

Science.gov (United States)

Torney, Colin J; Lamont, Myles; Debell, Leon; Angohiatok, Ryan J; Leclerc, Lisa-Marie; Berdahl, Andrew M

2018-05-19

Social interactions are a significant factor that influence the decision-making of species ranging from humans to bacteria. In the context of animal migration, social interactions may lead to improved decision-making, greater ability to respond to environmental cues, and the cultural transmission of optimal routes. Despite their significance, the precise nature of social interactions in migrating species remains largely unknown. Here we deploy unmanned aerial systems to collect aerial footage of caribou as they undertake their migration from Victoria Island to mainland Canada. Through a Bayesian analysis of trajectories we reveal the fine-scale interaction rules of migrating caribou and show they are attracted to one another and copy directional choices of neighbours, but do not interact through clearly defined metric or topological interaction ranges. By explicitly considering the role of social information on movement decisions we construct a map of near neighbour influence that quantifies the nature of information flow in these herds. These results will inform more realistic, mechanism-based models of migration in caribou and other social ungulates, leading to better predictions of spatial use patterns and responses to changing environmental conditions. Moreover, we anticipate that the protocol we developed here will be broadly applicable to study social behaviour in a wide range of migratory and non-migratory taxa.This article is part of the theme issue 'Collective movement ecology'. © 2018 The Authors.

Enhancing the Internet with the CONVERGENCE system an information-centric network coupled with a standard middleware

CERN Document Server

Andrade, Maria; Melazzi, Nicola; Walker, Richard; Hussmann, Heinrich; Venieris, Iakovos

2014-01-01

Convergence proposes the enhancement of the Internet with a novel, content-centric, publish–subscribe service model based on the versatile digital item (VDI): a common container for all kinds of digital content, including digital representations of real-world resources. VDIs will serve the needs of the future Internet, providing a homogeneous method for handling structured information, incorporating security and privacy mechanisms. CONVERGENCE subsumes the following areas of research: ·         definition of the VDI as a new fundamental unit of distribution and transaction; ·         content-centric networking functionality to complement or replace IP-address-based routing; ·         security and privacy protection mechanisms; ·         open-source middleware, including a community dictionary service to enable rich semantic searches; ·         applications, tested under real-life conditions. This book shows how CONVERGENCE allows publishing, searching and subscri...

Weather conditions associated with autumn migration by mule deer in Wyoming

Directory of Open Access Journals (Sweden)

Chadwick D. Rittenhouse

2015-06-01

Full Text Available Maintaining ecological integrity necessitates a proactive approach of identifying and acquiring lands to conserve unfragmented landscapes, as well as evaluating existing mitigation strategies to increase connectivity in fragmented landscapes. The increased use of highway underpasses and overpasses to restore connectivity for wildlife species offers clear conservation benefits, yet also presents a unique opportunity to understand how weather conditions may impact movement of wildlife species. We used remote camera observations (19,480 from an existing wildlife highway underpass in Wyoming and daily meteorological observations to quantify weather conditions associated with autumn migration of mule deer in 2009 and 2010. We identified minimal daily temperature and snow depth as proximate cues associated with mule deer migration to winter range. These weather cues were consistent across does and bucks, but differed slightly by year. Additionally, extreme early season snow depth or cold temperature events appear to be associated with onset of migration. This information will assist wildlife managers and transportation officials as they plan future projects to maintain and enhance migration routes for mule deer.

Trophic convergence drives morphological convergence in marine tetrapods.

Science.gov (United States)

Kelley, Neil P; Motani, Ryosuke

2015-01-01

Marine tetrapod clades (e.g. seals, whales) independently adapted to marine life through the Mesozoic and Caenozoic, and provide iconic examples of convergent evolution. Apparent morphological convergence is often explained as the result of adaptation to similar ecological niches. However, quantitative tests of this hypothesis are uncommon. We use dietary data to classify the feeding ecology of extant marine tetrapods and identify patterns in skull and tooth morphology that discriminate trophic groups across clades. Mapping these patterns onto phylogeny reveals coordinated evolutionary shifts in diet and morphology in different marine tetrapod lineages. Similarities in morphology between species with similar diets-even across large phylogenetic distances-are consistent with previous hypotheses that shared functional constraints drive convergent evolution in marine tetrapods.

Bird migration patterns in the arid southwest-Final report

Science.gov (United States)

Ruth, Janet M.; Felix, Rodney K.; Dieh, Robert H.

2010-01-01

To ensure full life-cycle conservation, we need to understand migrant behavior en route and how migrating species use stopover and migration aerohabitats. In the Southwest, birds traverse arid and mountainous landscapes in migration. Migrants are known to use riparian stopover habitats; we know less about how migrant density varies across the Southwest seasonally and annually, and how migrants use other habitat types during migratory stopover. Furthermore, we lack information about migrant flight altitudes, speeds, and directions of travel, and how these patterns vary seasonally and annually across the Southwest. Using weather surveillance radar data, we identified targets likely dominated by nocturnally migrating birds and determined their flight altitudes, speeds, directions over ground, and variations in abundance. Migrating or foraging bats likely are present across the region in some of these data, particularly in central Texas. We found that migrants flew at significantly lower altitudes and significantly higher speeds in spring than in fall. In all seasons migrants maintained seasonally appropriate directions of movement. We detected significant differences in vertical structure of migrant densities that varied both geographically within seasons and seasonally within sites. We also found that in fall there was a greater and more variable passage of migrants through the central part of the borderlands (New Mexico and west Texas); in spring there was some suggestion of greater and more variable passage of migrants in the eastern borderlands (central and south Texas). Such patterns are consistent with the existence of at least two migration systems through western North America and the use of different migration routes in spring and fall for at least some species. Using radar data and satellite land cover data, we determined the habitats with which migrants are associated during migration stopover. There were significant differences in bird densities among

Oceanic migration and spawning of anguillid eels.

Science.gov (United States)

Tsukamoto, K

2009-06-01

Many aspects of the life histories of anguillid eels have been revealed in recent decades, but the spawning migrations of their silver eels in the open ocean still remains poorly understood. This paper overviews what is known about the migration and spawning of anguillid species in the ocean. The factors that determine exactly when anguillid eels will begin their migrations are not known, although environmental influences such as lunar cycle, rainfall and river discharge seem to affect their patterns of movement as they migrate towards the ocean. Once in the ocean on their way to the spawning area, silver eels probably migrate in the upper few hundred metres, while reproductive maturation continues. Although involvement of a magnetic sense or olfactory cues seems probable, how they navigate or what routes they take are still a matter of speculation. There are few landmarks in the open ocean to define their spawning areas, other than oceanographic or geological features such as oceanic fronts or seamounts in some cases. Spawning of silver eels in the ocean has never been observed, but artificially matured eels of several species have exhibited similar spawning behaviours in the laboratory. Recent collections of mature adults and newly spawned preleptocephali in the spawning area of the Japanese eel Anguilla japonica have shown that spawning occurs during new moon periods in the North Equatorial Current region near the West Mariana Ridge. These data, however, show that the latitude of the spawning events can change among months and years depending on oceanographic conditions. Changes in spawning location of this and other anguillid species may affect their larval transport and survival, and appear to have the potential to influence recruitment success. A greater understanding of the spawning migration and the choice of spawning locations by silver eels is needed to help conserve declining anguillid species.

Policy Gradient SMDP for Resource Allocation and Routing in Integrated Services Networks

Science.gov (United States)

Vien, Ngo Anh; Viet, Nguyen Hoang; Lee, Seunggwan; Chung, Taechoong

In this paper, we solve the call admission control (CAC) and routing problem in an integrated network that handles several classes of calls of different values and with different resource requirements. The problem of maximizing the average reward (or cost) of admitted calls per unit time is naturally formulated as a semi-Markov Decision Process (SMDP) problem, but is too complex to allow for an exact solution. Thus in this paper, a policy gradient algorithm, together with a decomposition approach, is proposed to find the dynamic (state-dependent) optimal CAC and routing policy among a parameterized policy space. To implement that gradient algorithm, we approximate the gradient of the average reward. Then, we present a simulation-based algorithm to estimate the approximate gradient of the average reward (called GSMDP algorithm), using only a single sample path of the underlying Markov chain for the SMDP of CAC and routing problem. The algorithm enhances performance in terms of convergence speed, rejection probability, robustness to the changing arrival statistics and an overall received average revenue. The experimental simulations will compare our method's performance with other existing methods and show the robustness of our method.

Convergence in Multispecies Interactions.

Science.gov (United States)

Bittleston, Leonora S; Pierce, Naomi E; Ellison, Aaron M; Pringle, Anne

2016-04-01

The concepts of convergent evolution and community convergence highlight how selective pressures can shape unrelated organisms or communities in similar ways. We propose a related concept, convergent interactions, to describe the independent evolution of multispecies interactions with similar physiological or ecological functions. A focus on convergent interactions clarifies how natural selection repeatedly favors particular kinds of associations among species. Characterizing convergent interactions in a comparative context is likely to facilitate prediction of the ecological roles of organisms (including microbes) in multispecies interactions and selective pressures acting in poorly understood or newly discovered multispecies systems. We illustrate the concept of convergent interactions with examples: vertebrates and their gut bacteria; ectomycorrhizae; insect-fungal-bacterial interactions; pitcher-plant food webs; and ants and ant-plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

IT Convergence and Security 2012

CERN Document Server

Chung, Kyung-Yong

2013-01-01

The proceedings approaches the subject matter with problems in technical convergence and convergences of security technology. This approach is new because we look at new issues that arise from techniques converging. The general scope of the proceedings content is convergence security and the latest information technology. The intended readership are societies, enterprises, and research institutes, and intended content level is mid- to highly educated personals. The most important features and benefits of the proceedings are the introduction of the most recent information technology and its related ideas, applications and problems related to technology convergence, and its case studies and finally an introduction of converging existing security techniques through convergence security. Overall, through the proceedings, authors will be able to understand the most state of the art information strategies and technologies of convergence security.

Media Convergence: the Culture Dimensions of Thinking%Media Convergence:the Culture Dimensions of Thinking

Institute of Scientific and Technical Information of China (English)

Shen Diao; Lan Ju

2017-01-01

In the process of meida Convergence,many researchers paid excessive attention to media technology,industry and management,and ignored the culture dimensions of media convergence.Therefore,to transcend media convergence technology,industrial thinking and more to the particularity attach importance to cultural media,it is a right way to achieve media convergence.But in the context of China's culture,media convergence should value the cultural uniqueness and the imbalance of the realistic problems,to reach innovation and breakthrough.

Almost convergence of triple sequences

OpenAIRE

Ayhan Esi; M.Necdet Catalbas

2013-01-01

In this paper we introduce and study the concepts of almost convergence and almost Cauchy for triple sequences. Weshow that the set of almost convergent triple sequences of 0's and 1's is of the first category and also almost everytriple sequence of 0's and 1's is not almost convergent.Keywords: almost convergence, P-convergent, triple sequence.

Larval migration in PERL chambers as an in vitro model for percutaneous infection stimulates feeding in the canine hookworm Ancylostoma caninum

Directory of Open Access Journals (Sweden)

Welz Claudia

2011-01-01

Full Text Available Abstract Background Ancylostoma caninum third-stage larvae are the non-feeding infective stage of this parasite and are able to infect potential hosts via different infection routes. Since percutaneous infection is one of the most important routes and skin penetration is the first step into parasitic life, an existing in vitro model for percutaneous migration was modified and evaluated. The main parameter used to evaluate migration was the migration ratio (migrated larvae as a percentage of total number of larvae recovered. Additionally, the skin lag was calculated, expressing the percentage of larvae remaining in the skin and therefore not being recovered. Since initiation of feeding is proposed to be an important step in the transition from free-living to parasitic A. caninum larvae, feeding assays were performed with in vitro percutaneously migrated larvae. Additionally, infective larvae of A. caninum were activated via serum-stimulation and feeding behaviour was analysed and compared between percutaneously migrated and serum-stimulated larvae. Results Maximum skin migration levels of infective larvae were observed at temperatures above 32°C when larvae were placed on the epidermal side of skin for more than 12 hours. The medium beneath the skin had no effect on migration ratio, and no significant difference between the migration ratios through fresh and frozen/thawed skin was observed. Maximum feeding levels of 93.2% were observed for percutaneously migrated larvae after 48 h incubation, whereas serum-stimulated larvae reached the maximum of 91.0% feeding larvae after 24 h. Conclusions The PERL chamber system was optimised and standardised as an in vitro model for percutaneous migration. The larvae recovered after percutaneous migration showed characteristic signs of activation similar to that of serum-stimulated larvae. The observed difference in time course of resumption of feeding indicates that percutaneously migrated larvae are not

Route-external and route-internal landmarks in route descriptions : Effects of route length and map design

NARCIS (Netherlands)

Westerbeek, Hans; Maes, Alfons

2013-01-01

Landmarks are basic ingredients in route descriptions. They often mark choice points: locations where travellers choose from different options how to continue the route. This study focuses on one of the loose ends in the taxonomy of landmarks. In a memory-based production experiment in which

Societal response to nanotechnology: converging technologies–converging societal response research?

NARCIS (Netherlands)

Ronteltap, A.; Fischer, A.R.H.; Tobi, H.

2011-01-01

Nanotechnology is an emerging technology particularly vulnerable to societal unrest, which may hinder its further development. With the increasing convergence of several technological domains in the field of nanotechnology, so too could convergence of social science methods help to anticipate

Discrete Particle Swarm Optimization Routing Protocol for Wireless Sensor Networks with Multiple Mobile Sinks.

Science.gov (United States)

Yang, Jin; Liu, Fagui; Cao, Jianneng; Wang, Liangming

2016-07-14

Mobile sinks can achieve load-balancing and energy-consumption balancing across the wireless sensor networks (WSNs). However, the frequent change of the paths between source nodes and the sinks caused by sink mobility introduces significant overhead in terms of energy and packet delays. To enhance network performance of WSNs with mobile sinks (MWSNs), we present an efficient routing strategy, which is formulated as an optimization problem and employs the particle swarm optimization algorithm (PSO) to build the optimal routing paths. However, the conventional PSO is insufficient to solve discrete routing optimization problems. Therefore, a novel greedy discrete particle swarm optimization with memory (GMDPSO) is put forward to address this problem. In the GMDPSO, particle's position and velocity of traditional PSO are redefined under discrete MWSNs scenario. Particle updating rule is also reconsidered based on the subnetwork topology of MWSNs. Besides, by improving the greedy forwarding routing, a greedy search strategy is designed to drive particles to find a better position quickly. Furthermore, searching history is memorized to accelerate convergence. Simulation results demonstrate that our new protocol significantly improves the robustness and adapts to rapid topological changes with multiple mobile sinks, while efficiently reducing the communication overhead and the energy consumption.

Summable series and convergence factors

CERN Document Server

Moore, Charles N

1938-01-01

Fairly early in the development of the theory of summability of divergent series, the concept of convergence factors was recognized as of fundamental importance in the subject. One of the pioneers in this field was C. N. Moore, the author of the book under review.... Moore classifies convergence factors into two types. In type I he places the factors which have only the property that they preserve convergence for a convergent series or produce convergence for a summable series. In type II he places the factors which not only maintain or produce convergence but have the additional property that

Risk factors for venous port migration in a single institute in Taiwan.

Science.gov (United States)

Fan, Wen-Chieh; Wu, Cheng-Han; Tsai, Ming-Ju; Tsai, Ying-Ming; Chang, Hsu-Liang; Hung, Jen-Yu; Chen, Pei-Huan; Yang, Chih-Jen

2014-01-14

An implantable port device provides an easily accessible central route for long-term chemotherapy. Venous catheter migration is one of the rare complications of venous port implantation. It can lead to side effects such as pain in the neck, shoulder, or ear, venous thrombosis, and even life-threatening neurologic problems. To date, there are few published studies that discuss such complications. This retrospective study of venous port implantation in a single center, a Taiwan hospital, was conducted from January 2011 to March 2013. Venous port migration was recorded along with demographic and characteristics of the patients. Of 298 patients with an implantable import device, venous port migration had occurred in seven, an incidence rate of 2.3%. All seven were male and had received the Bard port Fr 6.6 which had smaller size than TYCO port Fr 7.5 and is made of silicon. Significantly, migration occurred in male patients (P = 0.0006) and in those with lung cancer (P = 0.004). Multivariable logistic regression analysis revealed that lung cancer was a significant risk factor for port migration (odds ratio: 11.59; P = 0.0059). The migration rate of the Bard port Fr 6.6 was 6.7%. The median time between initial venous port implantation and port migration was 35.4 days (range, 7 to 135 days) and 71.4% (5/7) of patients had port migration within 30 days after initial port implantation. Male sex and lung cancer are risk factors for venous port migration. The type of venous port is also an important risk factor.

Geolocator Data Reveal the Migration Route and Wintering Location of a Caribbean Martin (Progne dominicensis)

NARCIS (Netherlands)

Perlut, N.G.; Klak, T.C.; Rakhimberdiev, E.

2017-01-01

Caribbean Martins (Progne dominicensis)are common breeders on most Caribbean islands, where theyregularly roost and nest in urban areas from Februarythrough August. However, from September through January,the basic ecology of this species—its migration andwintering locations—are largely unknown. In

Routing Service Quality—Local Driver Behavior Versus Routing Services

DEFF Research Database (Denmark)

Ceikute, Vaida; Jensen, Christian S.

2013-01-01

of the quality of one kind of location-based service, namely routing services. Specifically, the paper presents a framework that enables the comparison of the routes provided by routing services with the actual driving behaviors of local drivers. Comparisons include route length, travel time, and also route...... popularity, which are enabled by common driving behaviors found in available trajectory data. The ability to evaluate the quality of routing services enables service providers to improve the quality of their services and enables users to identify the services that best serve their needs. The paper covers......Mobile location-based services is a very successful class of services that are being used frequently by users with GPS-enabled mobile devices such as smartphones. This paper presents a study of how to exploit GPS trajectory data, which is available in increasing volumes, for the assessment...

The Far East taiga forest: unrecognized inhospitable terrain for migrating Arctic-nesting waterbirds?

Directory of Open Access Journals (Sweden)

Xin Wang

2018-02-01

Full Text Available The degree of inhospitable terrain encountered by migrating birds can dramatically affect migration strategies and their evolution as well as influence the way we develop our contemporary flyway conservation responses to protect them. We used telemetry data from 44 tagged individuals of four large-bodied, Arctic breeding waterbird species (two geese, a swan and one crane species to show for the first time that these birds fly non-stop over the Far East taiga forest, despite their differing ecologies and migration routes. This implies a lack of suitable taiga refuelling habitats for these long-distance migrants. These results underline the extreme importance of northeast China spring staging habitats and of Arctic areas prior to departure in autumn to enable birds to clear this inhospitable biome, confirming the need for adequate site safeguard to protect these populations throughout their annual cycle.

Migration-induced architectures of planetary systems.

Science.gov (United States)

Szuszkiewicz, Ewa; Podlewska-Gaca, Edyta

2012-06-01

The recent increase in number of known multi-planet systems gives a unique opportunity to study the processes responsible for planetary formation and evolution. Special attention is given to the occurrence of mean-motion resonances, because they carry important information about the history of the planetary systems. At the early stages of the evolution, when planets are still embedded in a gaseous disc, the tidal interactions between the disc and planets cause the planetary orbital migration. The convergent differential migration of two planets embedded in a gaseous disc may result in the capture into a mean-motion resonance. The orbital migration taking place during the early phases of the planetary system formation may play an important role in shaping stable planetary configurations. An understanding of this stage of the evolution will provide insight on the most frequently formed architectures, which in turn are relevant for determining the planet habitability. The aim of this paper is to present the observational properties of these planetary systems which contain confirmed or suspected resonant configurations. A complete list of known systems with such configurations is given. This list will be kept by us updated from now on and it will be a valuable reference for studying the dynamics of extrasolar systems and testing theoretical predictions concerned with the origin and the evolution of planets, which are the most plausible places for existence and development of life.

Congestion control and routing over satellite networks

Science.gov (United States)

Cao, Jinhua

) method and then develop a novel on-demand routing system named Cross Entropy Accelerated Ant Routing System (CEAARS) for regular constellation LEO satellite networks. By implementing simulations on an Iridium-like satellite network, we compare the proposed CEAARS algorithm with the two approaches to adaptive routing protocols on the Internet: distance-vector (DV) and link-state (LS), as well as with the original Cross Entropy Ant Routing System (CEARS). DV algorithms are based on distributed Bellman Ford algorithm, and LS algorithms are implementation of Dijkstras single source shortest path. The results show that CEAARS not only remarkably improves the convergence speed of achieving optimal or suboptimal paths, but also reduces the number of overhead ants (management packets).

VANGL2 regulates membrane trafficking of MMP14 to control cell polarity and migration.

Science.gov (United States)

Williams, B Blairanne; Cantrell, V Ashley; Mundell, Nathan A; Bennett, Andrea C; Quick, Rachel E; Jessen, Jason R

2012-05-01

Planar cell polarity (PCP) describes the polarized orientation of cells within the plane of a tissue. Unlike epithelial PCP, the mechanisms underlying PCP signaling in migrating cells remain undefined. Here, the establishment of PCP must be coordinated with dynamic changes in cell adhesion and extracellular matrix (ECM) organization. During gastrulation, the membrane type-1 matrix metalloproteinase (MT1-MMP or MMP14) is required for PCP and convergence and extension cell movements. We report that the PCP protein Vang-like 2 (VANGL2) regulates the endocytosis and cell-surface availability of MMP14 in manner that is dependent on focal adhesion kinase. We demonstrate that zebrafish trilobite/vangl2 mutant embryos exhibit increased Mmp14 activity and decreased ECM. Furthermore, in vivo knockdown of Mmp14 partially rescues the Vangl2 loss-of-function convergence and extension phenotype. This study identifies a mechanism linking VANGL2 with MMP14 trafficking and suggests that establishment of PCP in migrating gastrula cells requires regulated proteolytic degradation or remodeling of the ECM. Our findings implicate matrix metalloproteinases as downstream effectors of PCP and suggest a broadly applicable mechanism whereby VANGL2 affects diverse morphogenetic processes.

The Topographic Design of River Channels for Form-Process Linkages.

Science.gov (United States)

Brown, Rocko A; Pasternack, Gregory B; Lin, Tin

2016-04-01

Scientists and engineers design river topography for a wide variety of uses, such as experimentation, site remediation, dam mitigation, flood management, and river restoration. A recent advancement has been the notion of topographical design to yield specific fluvial mechanisms in conjunction with natural or environmental flow releases. For example, the flow convergence routing mechanism, whereby shear stress and spatially convergent flow migrate or jump from the topographic high (riffle) to the low point (pool) from low to high discharge, is thought to be a key process able to maintain undular relief in gravel bedded rivers. This paper develops an approach to creating riffle-pool topography with a form-process linkage to the flow convergence routing mechanism using an adjustable, quasi equilibrium synthetic channel model. The link from form to process is made through conceptualizing form-process relationships for riffle-pool couplets into geomorphic covariance structures (GCSs) that are then quantitatively embedded in a synthetic channel model. Herein, GCSs were used to parameterize a geometric model to create five straight, synthetic river channels with varying combinations of bed and width undulations. Shear stress and flow direction predictions from 2D hydrodynamic modeling were used to determine if scenarios recreated aspects of the flow convergence routing mechanism. Results show that the creation of riffle-pool couplets that experience flow convergence in straight channels requires GCSs with covarying bed and width undulations in their topography as supported in the literature. This shows that GCSs are a useful way to translate conceptualizations of form-process linkages into quantitative models of channel form.

Convergence analysis of household expenditures using the absolute β-convergence method

Directory of Open Access Journals (Sweden)

Anto Domazet

2012-01-01

Full Text Available Background: The paper examines the convergence of household expenditures, in terms of a possible usage of the standardized, rather than consumer-tailored marketing, mainly on a regional level. Objectives: The main goal of this research is to study the existence of consumption expenditure convergence in the EU-27 countries, in the period between 2000 and 2007. Methods/Approach: The analysis used the absolute β-convergence method, in order to investigate the existence of a negative correlation between the growth over time in the overall consumption expenditure in EU member- countries for each individual product and service category and the initial expenditure level. Results: According to the obtained results, in the period between 2000 and 2007, the EU-27 countries reached a high level of consumer expenditure convergence, which provides a basis for developing a regional concept of the standardized international marketing for these countries’ markets. Conclusions: The results provide an empirical contribution to claims on consumer convergence in the countries included into economic integrations. Also, the obtained results can be used to create a basis for defining and applying the regional marketing concept for companies focusing on the EU-27 countries’ market.

First insights into the migration route and migratory connectivity of the Paddyfield Warbler using geolocator tagging and stable isotope analysis

Czech Academy of Sciences Publication Activity Database

Brlík, Vojtěch; Ilieva, M.; Lisovski, S.; Voigt, C. C.; Procházka, Petr

(2018) ISSN 0021-8375 R&D Projects: GA ČR GA13-06451S Institutional support: RVO:68081766 Keywords : Bird migration * Indo-European flyway * Light-level geolocation * Migration direction Impact factor: 1.468, year: 2016

Pre-spawning migration of adult Pacific lamprey, Entosphenus tridentatus, in the Willamette River, Oregon, U.S.A.

Science.gov (United States)

Clemens, Benjamin J.; Mesa, Matthew G.; Magie, Robert J.; Young, Douglas A.; Schreck, Carl B.

2012-01-01

We describe the migration distances and timing of the adult Pacific lamprey, Entosphenus tridentatus, in the Willamette River Basin (Oregon, U.S.A.). We conducted aerial surveys to track radio-tagged fish upstream of a major waterfall and hydropower complex en route to spawning areas. We detected 24 out of the 43 fish that passed the waterfall-hydropower complex. Of the detected fish, 17 were detected multiple times. Their maximum migration distance upstream in the mainstem Willamette approximated a normal distribution. The maximum distance migrated upstream did not significantly correlate with total body length (r = −0.186, P = 0.385) or date that the fish passed Willamette Falls (r = −0.118, P = 0.582). Fish migrated primarily during the spring to early summer period before stopping during the summer, when peak river temperatures (≥20°C). However, at least three fish continued to migrate upstream after September. Behavior ranged from relatively slow migration, followed by holding; to rapid migration, followed by slow migration further up in the basin. This study provides a basis for informing more detailed research on Pacific lamprey in the future.

Cultura da Convergência

Directory of Open Access Journals (Sweden)

Rogério Christofoletti

2008-12-01

Full Text Available Three ideas would suffice for the reading of “Cultura da Convergência” (Culture of Convergence by Henry Jenkins to be of interest to journalists and researchers in the area: media convergence as a cultural process; the strengthening of an emotional economy which guides consumers of symbolic goods and media creators; the expansion of trans-media narrative forms.

Cultura da Convergência

Directory of Open Access Journals (Sweden)

Rogério Christofoletti

2011-02-01

Full Text Available Three ideas would suffice for the reading of “Cultura da Convergência” (Culture of Convergence by Henry Jenkins to be of interest to journalists and researchers in the area: media convergence as a cultural process; the strengthening of an emotional economy which guides consumers of symbolic goods and media creators; the expansion of trans-media narrative forms.

Memory, not just perception, plays an important role in terrestrial mammalian migration.

Science.gov (United States)

Bracis, Chloe; Mueller, Thomas

2017-05-31

One of the key questions regarding the underlying mechanisms of mammalian land migrations is how animals select where to go. Most studies assume perception of resources as the navigational mechanism. The possible role of memory that would allow forecasting conditions at distant locations and times based on information about environmental conditions from previous years has been little studied. We study migrating zebra in Botswana using an individual-based simulation model, where perceptually guided individuals use currently sensed resources at different perceptual ranges, while memory-guided individuals use long-term averages of past resources to forecast future conditions. We compare simulated individuals guided by perception or memory on resource landscapes of remotely sensed vegetation data to trajectories of GPS-tagged zebras. Our results show that memory provides a clear signal that best directs migrants to their destination compared to perception at even the largest perceptual ranges. Zebras modelled with memory arrived two to four times, or up to 100 km, closer to the migration destination than those using perception. We suggest that memory in addition to perception is important for directing ungulate migration. Furthermore, our findings are important for the conservation of migratory mammals, as memory informing direction suggests migration routes could be relatively inflexible. © 2017 The Author(s).

An Adaptive Clustering Approach Based on Minimum Travel Route Planning for Wireless Sensor Networks with a Mobile Sink.

Science.gov (United States)

Tang, Jiqiang; Yang, Wu; Zhu, Lingyun; Wang, Dong; Feng, Xin

2017-04-26

In recent years, Wireless Sensor Networks with a Mobile Sink (WSN-MS) have been an active research topic due to the widespread use of mobile devices. However, how to get the balance between data delivery latency and energy consumption becomes a key issue of WSN-MS. In this paper, we study the clustering approach by jointly considering the Route planning for mobile sink and Clustering Problem (RCP) for static sensor nodes. We solve the RCP problem by using the minimum travel route clustering approach, which applies the minimum travel route of the mobile sink to guide the clustering process. We formulate the RCP problem as an Integer Non-Linear Programming (INLP) problem to shorten the travel route of the mobile sink under three constraints: the communication hops constraint, the travel route constraint and the loop avoidance constraint. We then propose an Imprecise Induction Algorithm (IIA) based on the property that the solution with a small hop count is more feasible than that with a large hop count. The IIA algorithm includes three processes: initializing travel route planning with a Traveling Salesman Problem (TSP) algorithm, transforming the cluster head to a cluster member and transforming the cluster member to a cluster head. Extensive experimental results show that the IIA algorithm could automatically adjust cluster heads according to the maximum hops parameter and plan a shorter travel route for the mobile sink. Compared with the Shortest Path Tree-based Data-Gathering Algorithm (SPT-DGA), the IIA algorithm has the characteristics of shorter route length, smaller cluster head count and faster convergence rate.

A Combination of Genetic Algorithm and Particle Swarm Optimization for Vehicle Routing Problem with Time Windows.

Science.gov (United States)

Xu, Sheng-Hua; Liu, Ji-Ping; Zhang, Fu-Hao; Wang, Liang; Sun, Li-Jian

2015-08-27

A combination of genetic algorithm and particle swarm optimization (PSO) for vehicle routing problems with time windows (VRPTW) is proposed in this paper. The improvements of the proposed algorithm include: using the particle real number encoding method to decode the route to alleviate the computation burden, applying a linear decreasing function based on the number of the iterations to provide balance between global and local exploration abilities, and integrating with the crossover operator of genetic algorithm to avoid the premature convergence and the local minimum. The experimental results show that the proposed algorithm is not only more efficient and competitive with other published results but can also obtain more optimal solutions for solving the VRPTW issue. One new well-known solution for this benchmark problem is also outlined in the following.

Implementation of Cooperation for Recycling Vehicle Routing Optimization in Two-Echelon Reverse Logistics Networks

Directory of Open Access Journals (Sweden)

Yong Wang

2018-04-01

Full Text Available The formation of a cooperative alliance is an effective means of approaching the vehicle routing optimization in two-echelon reverse logistics networks. Cooperative mechanisms can contribute to avoiding the inefficient assignment of resources for the recycling logistics operations and reducing long distance transportation. With regard to the relatively low performance of waste collection, this paper proposes a three-phase methodology to properly address the corresponding vehicle routing problem on two echelons. First, a bi-objective programming model is established to minimize the total cost and the number of vehicles considering semitrailers and vehicles sharing. Furthermore, the Clarke–Wright (CW savings method and the Non-dominated Sorting Genetic Algorithm-II (NSGA-II are combined to design a hybrid routing optimization heuristic, which is denoted CW_NSGA-II. Routes on the first and second echelons are obtained on the basis of sub-optimal solutions provided by CW algorithm. Compared to other intelligent algorithms, CW_NSGA-II reduces the complexity of the multi-objective solutions search and mostly converges to optimality. The profit generated by cooperation among retail stores and the recycling hub in the reverse logistics network is fairly and reasonably distributed to the participants by applying the Minimum Costs-Remaining Savings (MCRS method. Finally, an empirical study in Chengdu City, China, reveals the superiority of CW_NSGA over the multi-objective particle swarm optimization and the multi objective genetic algorithms in terms of solutions quality and convergence. Meanwhile, the comparison of MCRS method with the Shapley value model, equal profit method and cost gap allocation proves that MCRS method is more conducive to the stability of the cooperative alliance. In general, the implementation of cooperation in the optimization of the reverse logistics network effectively leads to the sustainable development of urban and sub

The long road to convergence and back. Convergence and crossmedia journalism at Dutch Newsmedia

NARCIS (Netherlands)

Tameling, Klaske; Broersma, Marcel

2012-01-01

KLASKE TAMELING & MARCEL BROERSMA The long road to convergence and back. Convergence and crossmedia journalism at Dutch Newsmedia Since the end of the twentieth century, convergence and cross-media journalism are concepts that are widely used to guide the future of journalism world wide. This study

E-cadherin is required for cranial neural crest migration in Xenopus laevis.

Science.gov (United States)

Huang, Chaolie; Kratzer, Marie-Claire; Wedlich, Doris; Kashef, Jubin

2016-03-15

The cranial neural crest (CNC) is a highly motile and multipotent embryonic cell population, which migrates directionally on defined routes throughout the embryo, contributing to facial structures including cartilage, bone and ganglia. Cadherin-mediated cell-cell adhesion is known to play a crucial role in the directional migration of CNC cells. However, migrating CNC co-express different cadherin subtypes, and their individual roles have yet to be fully explored. In previous studies, the expression of individual cadherin subtypes has been analysed using different methods with varying sensitivities, preventing the direct comparison of expression levels. Here, we provide the first comprehensive and comparative analysis of the expression of six cadherin superfamily members during different phases of CNC cell migration in Xenopus. By applying a quantitative RT-qPCR approach, we can determine the copy number and abundance of each expressed cadherin through different phases of CNC migration. Using this approach, we show for the first time expression of E-cadherin and XB/C-cadherin in CNC cells, adding them as two new members of cadherins co-expressed during CNC migration. Cadherin co-expression during CNC migration in Xenopus, in particular the constant expression of E-cadherin, contradicts the classical epithelial-mesenchymal transition (EMT) model postulating a switch in cadherin expression. Loss-of-function experiments further show that E-cadherin is required for proper CNC cell migration in vivo and also for cell protrusion formation in vitro. Knockdown of E-cadherin is not rescued by co-injection of other classical cadherins, pointing to a specific function of E-cadherin in mediating CNC cell migration. Finally, through reconstitution experiments with different E-cadherin deletion mutants in E-cadherin morphant embryos, we demonstrate that the extracellular domain, but not the cytoplasmic domain, of E-cadherin is sufficient to rescue CNC cell migration in vivo

State alternative route designations

International Nuclear Information System (INIS)

1989-07-01

Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select alternative routes. First,the state must establish a ''state routing agency,'' defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice of DOT of any alternative route designation before the routes are deemed effective

Migration velocity analysis using pre-stack wave fields

KAUST Repository

Alkhalifah, Tariq Ali

2016-08-25

Using both image and data domains to perform velocity inversion can help us resolve the long and short wavelength components of the velocity model, usually in that order. This translates to integrating migration velocity analysis into full waveform inversion. The migration velocity analysis part of the inversion often requires computing extended images, which is expensive when using conventional methods. As a result, we use pre-stack wavefield (the double-square-root formulation) extrapolation, which includes the extended information (subsurface offsets) naturally, to make the process far more efficient and stable. The combination of the forward and adjoint pre-stack wavefields provides us with update options that can be easily conditioned to improve convergence. We specifically use a modified differential semblance operator to split the extended image into a residual part for classic differential semblance operator updates and the image (Born) modelling part, which provides reflections for higher resolution information. In our implementation, we invert for the velocity and the image simultaneously through a dual objective function. Applications to synthetic examples demonstrate the features of the approach.

Hurricane Evacuation Routes

Data.gov (United States)

Department of Homeland Security — Hurricane Evacuation Routes in the United States A hurricane evacuation route is a designated route used to direct traffic inland in case of a hurricane threat. This...

Societal response to nanotechnology: converging technologies–converging societal response research?

International Nuclear Information System (INIS)

Ronteltap, Amber; Fischer, Arnout R. H.; Tobi, Hilde

2011-01-01

Nanotechnology is an emerging technology particularly vulnerable to societal unrest, which may hinder its further development. With the increasing convergence of several technological domains in the field of nanotechnology, so too could convergence of social science methods help to anticipate societal response. This paper systematically reviews the current state of convergence in societal response research by first sketching the predominant approaches to previous new technologies, followed by an analysis of current research into societal response to nanotechnology. A set of 107 papers on previous new technologies shows that rational actor models have played an important role in the study of societal response to technology, in particular in the field of information technology and the geographic region of Asia. Biotechnology and nuclear power have, in contrast, more often been investigated through risk perception and other affective determinants, particularly in Europe and the USA. A set of 42 papers on societal response to nanotechnology shows similarities to research in biotechnology, as it also builds on affective variables such as risk perception. Although there is a tendency to extend the rational models with affective variables, convergence in social science approaches to response to new technologies still has a long way to go. The challenge for researchers of societal response to technologies is to converge to some shared principles by taking up the best parts from the rational actor models dominant in information technology, whilst integrating non-rational constructs from biotechnology research. The introduction of nanotechnology gives a unique opportunity to do so.

Convergence of Nelson diffusions

International Nuclear Information System (INIS)

Dell'Antonio, G.; Posilicano, A.

1991-01-01

Let ψ t , ψ t n , n≥1, be solutions of Schroedinger equations with potentials form-bounded by -1/2 Δ and initial data in H 1 (R d ). Let P, P n , n≥1, be the probability measures on the path space Ω=C(R + , R d ) given by the corresponding Nelson diffusions. We show that if {ψ t n } n≥1 converges to ψ t in H 2 (R d ), uniformly in t over compact intervals, then {P n } n≥1 converges to P in total variation. Moreover, if the potentials are in the Kato class K d , we show that the above result follows from H 1 -convergence of initial data, and K d -convergence of potentials. (orig.)

Relations between information and communication technologies and international migration

Directory of Open Access Journals (Sweden)

Lukić Vesna

2017-01-01

asylum seekers have recently started. That can also be said for the research, where ICTs serve for gaining knowledge on migrants and attitudes towards immigrants. Although not voluminous, academic literature on the use and implications of ICTs use in the migration process in Serbia points to greater use of ICTs by certain groups of migrants (long-term settled refugees from former Yugoslavia in relation to the local population. There are also generational and gender differences in the use of ICTs by migrants. When it comes to transit asylum seekers in Serbia, the use of ICTs at various stages of migration and for various purposes (among them are the selection of the country of destination, the route of movement, but also contact with other migrants and smugglers is observed. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III47006

CONVERGENCE AND DIVERGENCE IN EUROPEAN UNION: EVIDENCE FOR BETA CONVERGENCE AMONG NEW EU MEMBER STATES

Directory of Open Access Journals (Sweden)

Ioana Sorina Mihuț

2013-07-01

Full Text Available Abstract: Convergence may be considered a central issue of the current economic literature, and not only, concentrating upon income distribution within different economies, but also focusing on different aspects of polarity and inequality that characterize especially the emerging economies. Testing convergence within economies may serve as a useful instrument for the validation of the economic growth models. While convergence was considered a defining element of the neoclassical growth models, the majority of the new endogenous growth models argue in favour of divergence across different economies. Testing convergence among European Union is even more challenging due to the high degree of heterogeneity that characterizes these economies. The recent accessions with ten new countries in 2004 and with another two in 2007 were considered only the first step towards assuring a sustainable convergence and finally adopting a common currency-the euro. A series of empirical studies concentrated upon testing convergence among EU, using as benchmark the real convergence quantified by the level of GDP/capita as an indicator for the living standards of every economy. The most popular approach rely on Beta and Sigma convergence, the first one being and indicator of the GDP/capita dispersion between different economies, and the later one being an estimator of the reverse relationship between GDP/capita and its initial level. The main purpose of this paper is to test Beta converge among the new EU member states, in order to obtained more information about the fact whether the poor countries are trying to catch-up with the more developed one. Also Beta convergence indicator embodies useful information about conditional and un-conditional convergence, two leading hypothesis within the neoclassical and endogenous growth models. For Beta convergence hypothesis to be valid it should be taken into consideration a ”catch-up” mechanism over a longer period of time

Migratory routes and at-sea threats to Pink-footed Shearwaters

Science.gov (United States)

Adams, Josh; Felis, Jonathan J.; Hodum, Peter; Colodro, Valentina; Carle, Ryan; López, Verónica

2016-01-01

The Pink-footed Shearwater (Ardenna creatopus) is a seabird with a breeding range restricted to three islands in Chile and an estimated world population of approximately 56,000 breeding individuals (Muñoz 2011, Oikonos unpublished data). Due to multiple threats on breeding colonies and at-sea, Pink-footed Shearwaters are listed as Endangered by the government of Chile (Reglamento de Clasificación de Especies, 2011), Threatened by the government of Canada (Environment Canada 2008), and are listed under Appendix 1 of the Agreement on the Conservation of Albatrosses and Petrels (ACAP 2013). A principal conservation concern for the species is mortality from fisheries bycatch during the breeding and non-breeding seasons; thus, identification of areas of overlap between at-sea use by Pink-footed Shearwaters and fisheries is a high priority conservation objective (Hinojosa Sáez and Hodum 1997, Mangel et al. 2013, ACAP 2013). During the non-breeding period, Pink-footed Shearwaters range as far north as Canada, although little was known until recently about migration routes and important wintering areas where fisheries bycatch could be a risk. Additionally, Pink-footed Shearwaters face at-sea threats during the non-breeding season off the west coast of North America. Recently, areas used by wintering Pink-footed Shearwaters have been identified as areas of interest for developing alternative energy offshore in North America (e.g., floating wind generators; Trident Winds 2016). The goal of our study was to track Pink-footed Shearwater post-breeding movements with satellite tags to identify timing and routes of migration, locate important non-breeding foraging habitats, and determine population distribution among different wintering regions.

Stable convergence and stable limit theorems

CERN Document Server

Häusler, Erich

2015-01-01

The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

The Hem protein mediates neuronal migration by inhibiting WAVE degradation and functions opposite of Abelson tyrosine kinase

Science.gov (United States)

Zhu, Zengrong; Bhat, Krishna Moorthi

2011-01-01

In the nervous system, neurons form in different regions, then they migrate and occupy specific positions. We have previously shown that RP2/sib, a well-studied neuronal pair in the Drosophila ventral nerve cord (VNC), has a complex migration route. Here, we show that the Hem protein, via the WAVE complex, regulates migration of GMC-1 and its progeny RP2 neuron. In Hem or WAVE mutants, RP2 neuron either abnormally migrates, crossing the midline from one hemisegment to the contralateral hemisegment, or does not migrate at al and fail to send out its axon projection. We report that Hem regulates neuronal migration through stabilizing WAVE. Since Hem and WAVE normally form a complex, our data argues that in the absence of Hem, WAVE, which is presumably no longer in a complex, becomes susceptible to degradation. We also find that Abelson Tyrosine kinase affects RP2 migration in a similar manner as Hem and WAVE, and appears to operate via WAVE. However, while Abl negatively regulates the levels of WAVE, it regulates migration via regulating the activity of WAVE. Our results also show that during the degradation of WAVE, Hem function is opposite to that of and downstream of Abl. PMID:21726548

Pseudo-Cycle-Based Multicast Routing in Wormhole-Routed Networks

Institute of Scientific and Technical Information of China (English)

SONG JianPing (宋建平); HOU ZiFeng (侯紫峰); XU Ming (许铭)

2003-01-01

This paper addresses the problem of fault-tolerant multicast routing in wormholerouted multicomputers. A new pseudo-cycle-based routing method is presented for constructing deadlock-free multicast routing algorithms. With at most two virtual channels this technique can be applied to any connected networks with arbitrary topologies. Simulation results show that this technique results in negligible performance degradation even in the presence of a large number of faulty nodes.

Routing in opportunistic networks

CERN Document Server

Dhurandher, Sanjay; Anpalagan, Alagan; Vasilakos, Athanasios

2013-01-01

This book provides a comprehensive guide to selected topics, both ongoing and emerging, in routing in OppNets. The book is edited by worldwide technical leaders, prolific researchers and outstanding academics, Dr. Isaac Woungang and co-editors, Dr. Sanjay Kumar Dhurandher, Prof. Alagan Anpalagan and Prof. Athanasios Vasilakos. Consisting of contributions from well known and high profile researchers and scientists in their respective specialties, the main topics that are covered in this book include mobility and routing, social-aware routing, context-based routing, energy-aware routing, incentive-aware routing, stochastic routing, modeling of intermittent connectivity, in both infrastructure and infrastructure-less OppNets. Key Features: Discusses existing and emerging techniques for routing in infrastructure and infrastructure-less OppNets. Provides a unified covering of otherwise disperse selected topics on routing in infrastructure and infrastructure-less OppNets.  Includes a set of PowerPoint slides and g...

Giant lobelias exemplify convergent evolution

Directory of Open Access Journals (Sweden)

Givnish Thomas J

2010-01-01

Full Text Available Abstract Giant lobeliads on tropical mountains in East Africa and Hawaii have highly unusual, giant-rosette growth forms that appear to be convergent on each other and on those of several independently evolved groups of Asteraceae and other families. A recent phylogenetic analysis by Antonelli, based on sequencing the widest selection of lobeliads to date, raises doubts about this paradigmatic example of convergent evolution. Here I address the kinds of evidence needed to test for convergent evolution and argue that the analysis by Antonelli fails on four points. Antonelli's analysis makes several important contributions to our understanding of lobeliad evolution and geographic spread, but his claim regarding convergence appears to be invalid. Giant lobeliads in Hawaii and Africa represent paradigmatic examples of convergent evolution.

A Multi-Attribute Pheromone Ant Secure Routing Algorithm Based on Reputation Value for Sensor Networks

Directory of Open Access Journals (Sweden)

Lin Zhang

2017-03-01

Full Text Available With the development of wireless sensor networks, certain network problems have become more prominent, such as limited node resources, low data transmission security, and short network life cycles. To solve these problems effectively, it is important to design an efficient and trusted secure routing algorithm for wireless sensor networks. Traditional ant-colony optimization algorithms exhibit only local convergence, without considering the residual energy of the nodes and many other problems. This paper introduces a multi-attribute pheromone ant secure routing algorithm based on reputation value (MPASR. This algorithm can reduce the energy consumption of a network and improve the reliability of the nodes’ reputations by filtering nodes with higher coincidence rates and improving the method used to update the nodes’ communication behaviors. At the same time, the node reputation value, the residual node energy and the transmission delay are combined to formulate a synthetic pheromone that is used in the formula for calculating the random proportion rule in traditional ant-colony optimization to select the optimal data transmission path. Simulation results show that the improved algorithm can increase both the security of data transmission and the quality of routing service.

A Multi-Attribute Pheromone Ant Secure Routing Algorithm Based on Reputation Value for Sensor Networks

Science.gov (United States)

Zhang, Lin; Yin, Na; Fu, Xiong; Lin, Qiaomin; Wang, Ruchuan

2017-01-01

With the development of wireless sensor networks, certain network problems have become more prominent, such as limited node resources, low data transmission security, and short network life cycles. To solve these problems effectively, it is important to design an efficient and trusted secure routing algorithm for wireless sensor networks. Traditional ant-colony optimization algorithms exhibit only local convergence, without considering the residual energy of the nodes and many other problems. This paper introduces a multi-attribute pheromone ant secure routing algorithm based on reputation value (MPASR). This algorithm can reduce the energy consumption of a network and improve the reliability of the nodes’ reputations by filtering nodes with higher coincidence rates and improving the method used to update the nodes’ communication behaviors. At the same time, the node reputation value, the residual node energy and the transmission delay are combined to formulate a synthetic pheromone that is used in the formula for calculating the random proportion rule in traditional ant-colony optimization to select the optimal data transmission path. Simulation results show that the improved algorithm can increase both the security of data transmission and the quality of routing service. PMID:28282894

The brain's dorsal route for speech represents word meaning: evidence from gesture.

Science.gov (United States)

Josse, Goulven; Joseph, Sabine; Bertasi, Eric; Giraud, Anne-Lise

2012-01-01

The dual-route model of speech processing includes a dorsal stream that maps auditory to motor features at the sublexical level rather than at the lexico-semantic level. However, the literature on gesture is an invitation to revise this model because it suggests that the premotor cortex of the dorsal route is a major site of lexico-semantic interaction. Here we investigated lexico-semantic mapping using word-gesture pairs that were either congruent or incongruent. Using fMRI-adaptation in 28 subjects, we found that temporo-parietal and premotor activity during auditory processing of single action words was modulated by the prior audiovisual context in which the words had been repeated. The BOLD signal was suppressed following repetition of the auditory word alone, and further suppressed following repetition of the word accompanied by a congruent gesture (e.g. ["grasp" + grasping gesture]). Conversely, repetition suppression was not observed when the same action word was accompanied by an incongruent gesture (e.g. ["grasp" + sprinkle]). We propose a simple model to explain these results: auditory and visual information converge onto premotor cortex where it is represented in a comparable format to determine (in)congruence between speech and gesture. This ability of the dorsal route to detect audiovisual semantic (in)congruence suggests that its function is not restricted to the sublexical level.

Effect of Migration Pathway on Travel Time and Survival of Acoustic-Tagged Juvenile Salmonids in the Columbia River Estuary

Energy Technology Data Exchange (ETDEWEB)

Harnish, Ryan A.; Johnson, Gary E.; McMichael, Geoffrey A.; Hughes, Michael S.; Ebberts, Blaine D.

2012-02-01

Off-channel areas (side channels, tidal flats, sand bars, and shallow-water bays) may serve as important migration corridors through estuarine environments for salmon and steelhead smolts. Relatively large percentages (21-33%) of acoustic-tagged yearling and subyearling Chinook salmon and steelhead smolts were detected migrating through off-channel areas of the Columbia River estuary in 2008. The probability of survival for off-channel migrants (0.78-0.94) was similar to or greater than the survival probability of main channel migrants (0.67-0.93). Median travel times were similar for all species or run types and migration pathways we examined, ranging from 1-2 d. The route used by smolts to migrate through the estuary may affect their vulnerability to predation. Acoustic-tagged steelhead that migrated nearest to avian predator nesting colonies experienced higher predation rates (24%) than those that migrated farthest from the colonies (10%). The use of multiple migration pathways may be advantageous to out-migrating smolts because it helps to buffer against high rates of mortality, which may occur in localized areas, and helps to minimize inter- and intraspecific competition.

Convergence

DEFF Research Database (Denmark)

Madsen, Ole Brun; Nielsen, Jens Frederik Dalsgaard; Schiøler, Henrik

2002-01-01

Convergence trends between the WAN Internet area, characterized by best effort service provision, and the real time LAN domain, with requirements for guaranteed services, are identified and discussed. A bilateral evolution is identified, where typical bulk service applications from WAN, such as m......Convergence trends between the WAN Internet area, characterized by best effort service provision, and the real time LAN domain, with requirements for guaranteed services, are identified and discussed. A bilateral evolution is identified, where typical bulk service applications from WAN...... with the emergence of remote service provision, such as supervision and control of decentralized heating facilities and wind based electrical power production. The reliability issue is addressed from a structural viewpoint, where the concept of Structural QoS (SQoS) is defined to support reliability modelling...

Factors Affecting Route Selection and Survival of Steelhead Kelts at Snake River Dams in 2012 and 2013

Energy Technology Data Exchange (ETDEWEB)

Harnish, Ryan A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Colotelo, Alison HA [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Li, Xinya [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ham, Kenneth D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deng, Zhiqun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-12-01

In 2012 and 2013, Pacific Northwest National Laboratory conducted a study that summarized the passage proportions and route-specific survival rates of steelhead kelts that passed through Federal Columbia River Power System (FCRPS) dams. To accomplish this, a total of 811 steelhead kelts were tagged with Juvenile Salmon Acoustic Telemetry System (JSATS) transmitters. Acoustic receivers, both autonomous and cabled, were deployed throughout the FCRPS to monitor the downstream movements of tagged-kelts. Kelts were also tagged with Passive Integrated Transponder tags to monitor passage through juvenile bypass systems and detect returning fish. The current study evaluated data collected in 2012 and 2013 to identify individual, behavioral, environmental and dam operation variables that were related to passage and survival of steelhead kelts that passed through FCRPS dams. Bayesian model averaging of multivariable logistic regression models was used to identify the environmental, temporal, operational, individual, and behavioral variables that had the highest probability of influencing the route of passage and the route-specific survival probabilities for kelts that passed Lower Granite (LGR), Little Goose (LGS), and Lower Monumental (LMN) dams in 2012 and 2013. The posterior probabilities of the best models for predicting route of passage ranged from 0.106 for traditional spill at LMN to 0.720 for turbine passage at LGS. Generally, the behavior (depth and near-dam searching activity) of kelts in the forebay appeared to have the greatest influence on their route of passage. Shallower-migrating kelts had a higher probability of passing via the weir and deeper-migrating kelts had a higher probability of passing via the JBS and turbines than other routes. Kelts that displayed a higher level of near-dam searching activity had a higher probability of passing via the spillway weir and those that did less near-dam searching had a higher probability of passing via the JBS and

Planning routes around the world: International evidence for southern route preferences

NARCIS (Netherlands)

Brunyé, Tad T.; Andonova, Elena; Meneghetti, Chiara; Noordzij, Matthijs Leendert; Pazzaglia, Francesca; Wienemann, Rasmus; Mahoney, Caroline R.; Taylor, Holly A.

2012-01-01

Three studies test whether the southern route preference, which describes the tendency for route planners to disproportionately select south- rather than north-going routes, can be attributed to regional elevation patterns; specifically, we ask whether this effect replicates in three topographically

A preliminary study of international migration of the Chinese people.

Science.gov (United States)

Zhu, G

1994-01-01

International Chinese migration has spanned five periods: 1) an initial period of random and short-term migration dating back to the Qing and Han dynasties; 2) a spontaneous period since the Sui and Tang dynasties along trade routes; 3) a transition period during the Ming dynasty and the early Qing dynasty with war, poverty, and population growth as push factors; 4) peak migration during the Opium War period due to economic depression, population pressure, and the "coolie" trade; and 5) continuous development between the 1920s and 1949. Migration tended to occur between Guangdong and Fujian provinces and other southeast Asian countries. Four factors were identified as necessary for international migration to occur: the origin of migration, the destination factor, the middle link factor, and the immigrant characteristics. The origins of early Chinese migration appeared in a country of political corruption, population pressure, a backward economy, and social chaos. The pull factors at destination end were demand for labor. The middle link was the short distance between Guangdong and Fujian provinces and southeast Asian countries and longstanding nongovernmental exchanges. Other links were the similarity of climate, similar racial features, cultural lifestyle similarities, and convenient transportation. The people in these two provinces had a history of migration and a personality suitable for the spirit of adventure. Peak migration occurred during the late Qing dynasty and during the continuous development period. Between 1840 and 1911 there were about 10 million Chinese immigrants and during 1911 and 1949 there were about 6 million. In general, over 20 million immigrated prior to 1949, of which about 50% migrated during the peak period, 33% during the continuous period, and 20% before 1840. This amounted to about 33% of European migration and two times African migration. 60% were from Guangdong, and 30% were from Fujian province, of whom most were from counties

Risk factors for venous port migration in a single institute in Taiwan

OpenAIRE

Fan, Wen-Chieh; Wu, Cheng-Han; Tsai, Ming-Ju; Tsai, Ying-Ming; Chang, Hsu-Liang; Hung, Jen-Yu; Chen, Pei-Huan; Yang, Chih-Jen

2014-01-01

Background An implantable port device provides an easily accessible central route for long-term chemotherapy. Venous catheter migration is one of the rare complications of venous port implantation. It can lead to side effects such as pain in the neck, shoulder, or ear, venous thrombosis, and even life-threatening neurologic problems. To date, there are few published studies that discuss such complications. Methods This retrospective study of venous port implantation in a single center, a Taiw...

Proposals for the Negotiation Process on the United Nations Global Compact for Migration

Directory of Open Access Journals (Sweden)

Victor Genina

2017-09-01

• builds a cooperation-oriented, peer-review mechanism to review migration policies.    The paper has been conceived as an input for those who will take part in the negotiation of the global compact for migration, as well as those who will closely follow those negotiations. Thus, the paper assumes a level of knowledge on how international migration has been addressed within the United Nations during the last several years and of the complexities of these negotiation processes. The author took part in different UN negotiation processes on international migration from 2004 to 2013. The paper is primarily based on this experience.[4] [1] G.A. Res. 71/1, ¶ 21 (Sept. 19, 2016. [2] G.A. Res. 68/4 (Oct. 3, 2013. [3] A mixed flow, according to UNHCR (n.d., is the migratory flow comprised by both asylum seekers and migrants: “Migrants and refugees increasingly make use of the same routes and means of transport to get to an overseas destination.” [4] During that period, the author was a staff member of the Mexican delegation to the United Nations, both in Geneva and New York.

Disentangling migratory routes and wintering grounds of Iberian near-threatened European Rollers Coracias garrulus.

Directory of Open Access Journals (Sweden)

Juan Rodríguez-Ruiz

Full Text Available Long-distance migrants are suffering drastic declines in the last decades. Causes beneath this problem are complex due to the wide spatial and temporal scale involved. We aim to reveal migratory routes, stopover areas, wintering grounds, and migratory strategies for the most southwestern populations of the near-threatened European Roller Coracias garrulus in order to identify conservation key areas for the non-breeding stage of this species. To this end, we used tracking data from seven satellite transmitters fitted to birds breeding in different populations throughout the Iberian Peninsula and four geolocators fitted to individuals in a southeastern Iberian population. Precise satellite data were used to describe daily activity patterns and speed in relation to the main regions crossed during the migration. Individuals from the most southwestern Iberian populations made a detour towards the Atlantic African coast whereas those from northeastern populations followed a straight north-to-south route. We identified important stopover areas in the Sahel belt, mainly in the surroundings of the Lake Chad, and wintering grounds on southwestern Africa farther west than previously reported for the species. Concerning the migratory strategy, satellite data revealed: 1 a mainly nocturnal flying activity, 2 that migration speed depended on the type of crossed habitat, with higher average speed while crossing the desert; and 3 that the migration was slower and lasted longer in autumn than in spring. The studied populations showed weak migratory connectivity, suggesting the confluence of birds from a wide range of breeding grounds in a restricted wintering area. Therefore, we suggest to target on defining precisely key areas for this species and identifying specific threats in them in order to develop an appropriate global conservation programme for the European Roller.

Migration of Gelfoam to the gallbladder after liver biopsy

Energy Technology Data Exchange (ETDEWEB)

Riddle, Chris [The Hospital for Sick Children, Image Guided Therapy, Department of Diagnostic Imaging, Toronto (Canada); Dalhousie University, School of Medicine, Halifax (Canada); Ahmed, Bilal [University of Toronto School of Medicine, Toronto (Canada); Doyle, John [The Hospital for Sick Children, Department of Hematology/Oncology, Toronto (Canada); Connolly, Bairbre L. [The Hospital for Sick Children, Image Guided Therapy, Department of Diagnostic Imaging, Toronto (Canada)

2008-07-15

Liver biopsy is a common procedure, with an inherent risk of bleeding. There are different ways to help avoid hemorrhage, including biopsy through a transjugular venous route or embolization of the tract with liquid or solid materials. We describe an image-guided percutaneous core needle liver biopsy with tract embolization using thick Gelfoam slurry in a pediatric oncology patient. Imaging studies acquired after the biopsy indicated that the Gelfoam mixture had likely migrated to the gallbladder and common bile duct. We report this rare occurrence with its striking imaging in order to make those performing biopsies aware of this possibility. (orig.)

Understanding the Impact of Environmental Variability on Anchovy Overwintering Migration in the Black Sea and its Implications for the Fishing Industry

Directory of Open Access Journals (Sweden)

Ceren Guraslan

2017-08-01

Full Text Available Black Sea anchovy (Engraulis encrasicolus undertake extensive overwintering migrations every fall from nursery grounds to warmer overwintering areas located on the south-eastern coast of the Black Sea. During migration and particularly upon arrival at the Anatolian coast, they support an important fishery and valuable source of income for the regional community. Black Sea anchovy have undergone significant stock fluctuations partly related to climatic conditions; for example, migrating anchovy schools arrived late or failed to arrive at the Anatolian coast when fall temperatures increased. It is therefore of importance to understand the conditions required for successful overwintering migration and explore different migration routes. This study invokes a Lagrangian modeling approach applied to satellite derived circulation and temperature data as a first attempt to model anchovy migration dynamics in the Black Sea. This modeling approach takes the influence of the physical environment into account, while the quality of overwintering grounds, adaptive, schooling, and homing behavior is neglected. The model is used to investigate the possible influence of interannual and seasonal variability of temperature and surface currents, as well as the influence of migration behavior on the success of anchovy overwintering migration for both the Black Sea and Azov Sea anchovy. The results of the present work show the possibility that overwintering anchovy fished along the Turkish Eastern Anatolian coast may not exclusively originate from the northwestern shelf, but mainly from the eastern Black Sea basin. Migration pathways are identified for both Black Sea and Azov Sea anchovy, which are of importance for the national fisheries efforts of riparian countries. The modeling results are in agreement with general patterns of anchovy migration given in the literature indicating that the physical environment may be a major factor in shaping general migration

Implantable central venous chemoport: camparision of results according to approach routes and methods

International Nuclear Information System (INIS)

Shin, Byung Suck; Ahn, Moon Sang

2003-01-01

To evaluate the results and complications of placement of implantable port according to approach routes and methods. Between April 2001 and October 2002, a total of 103 implantable chemoport was placed in 95 patients for chemotherapy using preconnected type (n=39) and attachable type (n=64). Puncture sites were left subclavian vein (n=35), right subclavian vein (n=5), left internal jugular vein (n=9), right internal jugular vein (n=54). We evaluated duration of catheterization days, complications according to approach routes and methods. Implantable chemoport was placed successfully in all cases. Duration of catheterization ranged from 8 to 554 days(mean 159, total 17,872 catheter days). Procedure related complications occurred transient pulmonary air embolism (n=1), small hematoma (n=1) and malposition in using preconnected type (n=2). Late complications occurred catheter migration (n=5), catheter malfunction (n=3), occlusion (n=1) and infection (n=11). Among them 15 chemoport was removed (14.5%). Catheter migration was occured via subclavian vein in all cases (13%, p=.008). Infection developed in 10.7% of patients(0.61 per 1000 catheter days). There were no catheter-related central vein thrombosis. Implantation of chemoport is a safe procedure. Choice of right internal jugular vein than subclavian vain vein for puncture site has less complications. And selection of attachable type of chemoport is convenient than preconnected type. Adequate care of chemoport is essential for long patency

Convergence from divergence

Science.gov (United States)

Costin, Ovidiu; Dunne, Gerald V.

2018-01-01

We show how to convert divergent series, which typically occur in many applications in physics, into rapidly convergent inverse factorial series. This can be interpreted physically as a novel resummation of perturbative series. Being convergent, these new series allow rigorous extrapolation from an asymptotic region with a large parameter, to the opposite region where the parameter is small. We illustrate the method with various physical examples, and discuss how these convergent series relate to standard methods such as Borel summation, and also how they incorporate the physical Stokes phenomenon. We comment on the relation of these results to Dyson’s physical argument for the divergence of perturbation theory. This approach also leads naturally to a wide class of relations between bosonic and fermionic partition functions, and Klein-Gordon and Dirac determinants.

Convergent evolution and divergent selection: lizards at the White Sands ecotone.

Science.gov (United States)

Rosenblum, Erica Bree

2006-01-01

Ecological transition zones, where organismal phenotypes result from a delicate balance between selection and migration, highlight the interplay of local adaptation and gene flow. Here, I study the response of an entire species assemblage to natural selection across a common ecotone. Three lizard species, distributed along a dramatic environmental gradient in substrate color, display convergent adaptation of blanched coloration on the gypsum dunes of White Sands National Monument. I investigate the role of gene flow in modulating phenotypic response to selection by quantifying color variation and genetic variation across the ecotone. I find species differences in degree of background matching and in genetic connectivity of populations across the ecotone. Differences among species in phenotypic response to selection scale precisely to levels of genetic isolation. Species with higher levels of gene flow across the ecotone exhibit less dramatic responses to selection. Results also reveal a strong signal of ecologically mediated divergence for White Sands lizards. For all species, phenotypic variation is better explained by habitat similarity than genetic similarity. Convergent evolution of blanched coloration at White Sands clearly reflects the action of strong divergent selection; however, adaptive response appears to be modulated by gene flow and demographic history and can be predicted by divergence-with-gene-flow models.

Density by Moduli and Lacunary Statistical Convergence

Directory of Open Access Journals (Sweden)

Vinod K. Bhardwaj

2016-01-01

Full Text Available We have introduced and studied a new concept of f-lacunary statistical convergence, where f is an unbounded modulus. It is shown that, under certain conditions on a modulus f, the concepts of lacunary strong convergence with respect to a modulus f and f-lacunary statistical convergence are equivalent on bounded sequences. We further characterize those θ for which Sθf=Sf, where Sθf and Sf denote the sets of all f-lacunary statistically convergent sequences and f-statistically convergent sequences, respectively. A general description of inclusion between two arbitrary lacunary methods of f-statistical convergence is given. Finally, we give an Sθf-analog of the Cauchy criterion for convergence and a Tauberian theorem for Sθf-convergence is also proved.

Vadose zone flow convergence test suite

Energy Technology Data Exchange (ETDEWEB)

Butcher, B. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-06-05

Performance Assessment (PA) simulations for engineered disposal systems at the Savannah River Site involve highly contrasting materials and moisture conditions at and near saturation. These conditions cause severe convergence difficulties that typically result in unacceptable convergence or long simulation times or excessive analyst effort. Adequate convergence is usually achieved in a trial-anderror manner by applying under-relaxation to the Saturation or Pressure variable, in a series of everdecreasing RELAxation values. SRNL would like a more efficient scheme implemented inside PORFLOW to achieve flow convergence in a more reliable and efficient manner. To this end, a suite of test problems that illustrate these convergence problems is provided to facilitate diagnosis and development of an improved convergence strategy. The attached files are being transmitted to you describing the test problem and proposed resolution.

Transportation routing analysis geographic information system -- TRAGIS, a multimodal transportation routing tool

International Nuclear Information System (INIS)

Johnson, P.E.

1995-01-01

Over 15 years ago, Oak Ridge National Laboratory (ORNL) developed two transportation routing models: HIGHWAY, which predicts truck transportation routes, and INTERLINE, which predicts rail transportation routes. Subsequent modifications have been made to enhance each of these models. Some of these changes include population density information for routes, HM-164 routing regulations for highway route controlled quantities of radioactive materials (RAM) truck shipments, and inclusion of waterway routing into INTERLINE. The AIRPORT model, developed 2 years after the HIGHWAY and INTERLINE models, serves as an emergency response tool. This model identifies the nearest airports from a designated location. Currently, the AIRPORT model is inactive. The Transportation Management Division of the US Department of Energy held a Baseline Requirements Assessment Session on the HIGHWAY, INTERLINE, and AIRPORT models in April 1994 to bring together many users of these models and other experts in the transportation routing field to discuss these models and to decide on the capabilities that needed to be added. Of the many needs discussed, the primary one was to have the network databases within a geographic information system (GIS). As a result of the Baseline Requirements Session, the development of a new GIS model has been initiated. This paper will discuss the development of the new Transportation Routing Analysis GIS (TRAGIS) model at ORNL

VINE ROUTES IN BULGARIA

Directory of Open Access Journals (Sweden)

Lyuben Hristov

2015-03-01

Full Text Available The article deals with a scheme for the modern vine route in Bulgaria. Five basic vine routes and one international, between Bulgaria, Macedonia and Greece are defined. All routes consider characteristic varieties of grapes and kinds of vine products. Vine tourist products combined with visits of important natural and anthropological object are in the bases of the defined routes. The described routes are an important contribution to development of alternative tourist products in the country.

Robust against route failure using power proficient reliable routing in MANET

Directory of Open Access Journals (Sweden)

M. Malathi

2018-03-01

Full Text Available The aim of this paper was to propose a novel routing protocol for Mobile Adhoc Network communication which reduces the route failure during transmission. The proposed routing protocol uses 3 salient parameters to discover the path which ensure the reliable communication. The quality of the channel, link quality and energy level of the node are the major reasons for unintentional node failure in mobile Adhoc network. So the proposed routing protocol considers these three parameters to select the best forwarder node in the path. The reliable data communication is achieved by transmitting data via path selected by the proposed routing scheme has been proven using network simulator (NS2. Keywords: Channel quality, Link quality, Mobile Adhoc Network (MANET, Residual energy

Morphological convergence in ‘river dolphin’ skulls

Directory of Open Access Journals (Sweden)

Charlotte E. Page

2017-11-01

Full Text Available Convergent evolution can provide insights into the predictability of, and constraints on, the evolution of biodiversity. One striking example of convergence is seen in the ‘river dolphins’. The four dolphin genera that make up the ‘river dolphins’ (Inia geoffrensis, Pontoporia blainvillei, Platanista gangetica and Lipotes vexillifer do not represent a single monophyletic group, despite being very similar in morphology. This has led many to using the ‘river dolphins’ as an example of convergent evolution. We investigate whether the skulls of the four ‘river dolphin’ genera are convergent when compared to other toothed dolphin taxa in addition to identifying convergent cranial and mandibular features. We use geometric morphometrics to uncover shape variation in the skulls of the ‘river dolphins’ and then apply a number of phylogenetic techniques to test for convergence. We find significant convergence in the skull morphology of the ‘river dolphins’. The four genera seem to have evolved similar skull shapes, leading to a convergent morphotype characterised by elongation of skull features. The cause of this morphological convergence remains unclear. However, the features we uncover as convergent, in particular elongation of the rostrum, support hypotheses of shared feeding mode or diet and thus provide the foundation for future work into convergence within the Odontoceti.

Testing Convergence Versus History: Convergence Dominates Phenotypic Evolution for over 150 Million Years in Frogs.

Science.gov (United States)

Moen, Daniel S; Morlon, Hélène; Wiens, John J

2016-01-01

Striking evolutionary convergence can lead to similar sets of species in different locations, such as in cichlid fishes and Anolis lizards, and suggests that evolution can be repeatable and predictable across clades. Yet, most examples of convergence involve relatively small temporal and/or spatial scales. Some authors have speculated that at larger scales (e.g., across continents), differing evolutionary histories will prevent convergence. However, few studies have compared the contrasting roles of convergence and history, and none have done so at large scales. Here we develop a two-part approach to test the scale over which convergence can occur, comparing the relative importance of convergence and history in macroevolution using phylogenetic models of adaptive evolution. We apply this approach to data from morphology, ecology, and phylogeny from 167 species of anuran amphibians (frogs) from 10 local sites across the world, spanning ~160 myr of evolution. Mapping ecology on the phylogeny revealed that similar microhabitat specialists (e.g., aquatic, arboreal) have evolved repeatedly across clades and regions, producing many evolutionary replicates for testing for morphological convergence. By comparing morphological optima for clades and microhabitat types (our first test), we find that convergence associated with microhabitat use dominates frog morphological evolution, producing recurrent ecomorphs that together encompass all sampled species in each community in each region. However, our second test, which examines whether and how much species differ from their inferred optima, shows that convergence is incomplete: that is, phenotypes of most species are still somewhat distant from the estimated optimum for each microhabitat, seemingly because of insufficient time for more complete adaptation (an effect of history). Yet, these effects of history are related to past ecologies, and not clade membership. Overall, our study elucidates the dominant drivers of

Weak entropy inequalities and entropic convergence

Institute of Scientific and Technical Information of China (English)

2008-01-01

A criterion for algebraic convergence of the entropy is presented and an algebraic convergence result for the entropy of an exclusion process is improved. A weak entropy inequality is considered and its relationship to entropic convergence is discussed.

Convergence of mayer expansions

International Nuclear Information System (INIS)

Brydges, D.C.

1986-01-01

The tree graph bound of Battle and Federbush is extended and used to provide a simple criterion for the convergence of (iterated) Mayer expansions. As an application estimates on the radius of convergence of the Mayer expansion for the two-dimensional Yukawa gas (nonstable interaction) are obtained

Post-breeding migration of Dutch-breeding black-tailed godwits: timing, routes, use of stopovers, and nonbreeding destinations

Science.gov (United States)

Hooijmeijer, Jos C. E. W.; Senner, Nathan R.; Tibbitts, T. Lee; Gill, Robert E.; Douglas, David C.; Bruinzeel, Leo W.; Wymenga, Eddy; Piersma, Theunis

2014-01-01

Conservation of long-distance migratory shorebirds is complex because these species use habitats spread across continents and hemispheres, making identification of critical habitats and potential bottlenecks in the annual cycle especially difficult. The population of Black-tailed Godwits that breeds in Western Europe, Limosa limosa limosa, has declined precipitously over the past few decades. Despite significant efforts to identify the root causes of this decline, much remains unclear. To better understand the migratory timing, use of stopover and nonbreeding sites, and the potential impact of breeding success on these parameters, we attached 15 Argos satellite transmitters and 10 geolocation tracking devices to adult godwits nearing completion of incubation at breeding sites in southwest Friesland, The Netherlands during the spring of 2009. We successfully tracked 16 adult godwits for their entire southward migration and two others for part of it. Three migration patterns and four regions of use were apparent. Most godwits left their breeding sites and proceeded south directly to stopover sites in the Mediterranean — e.g. Spain, Portugal, and Morocco — before flying on to non-breeding sites in West Africa. Other individuals spent the entire nonbreeding season in the Mediterranean. A third pattern included a few individuals that flew nonstop from their Dutch breeding sites to nonbreeding sites in West Africa. Tracking data from this study will be immediately useful for conservation efforts focused on preserving the dispersed network of sites used by godwits during their southward migration.

The C. elegans tailless/Tlx homolog nhr-67 regulates a stage-specific program of linker cell migration in male gonadogenesis.

Science.gov (United States)

Kato, Mihoko; Sternberg, Paul W

2009-12-01

Cell migration is a common event during organogenesis, yet little is known about how migration is temporally coordinated with organ development. We are investigating stage-specific programs of cell migration using the linker cell (LC), a migratory cell crucial for male gonadogenesis of C. elegans. During the L3 and L4 larval stages of wild-type males, the LC undergoes changes in its position along the migratory route, in transcriptional regulation of the unc-5 netrin receptor and zmp-1 zinc matrix metalloprotease, and in cell morphology. We have identified the tailless homolog nhr-67 as a cell-autonomous, stage-specific regulator of timing in LC migration programs. In nhr-67-deficient animals, each of the L3 and L4 stage changes is either severely delayed or never occurs, yet LC development before the early L3 stage or after the mid-L4 stage occurs with normal timing. We propose that there is a basal migration program utilized throughout LC migration that is modified by stage-specific regulators such as nhr-67.

Integrational Models and Forms of Inter-State Public-Private Partnership: Aspects of Financial Convergence

Directory of Open Access Journals (Sweden)

ALINA KULAI

2015-10-01

Full Text Available In the article we examined the main models and forms of public-private partnership, their role in the socio-economic development and deepening of financial convergence of countries-participants of the partnership. The attention was paid to decentralization of inter-state forms of public-private partnership as the basis of cross-border and transnational partnership. The scientific research, described in this publication, have found their practical application in the realization of the project within Euro-region “Bug”. This project has founded a joined Ukrainian – Polish institution of labor migration administration and also of granting necessary permissions for realization activities within Ukraine.

Climate change alters the optimal wind-dependent flight routes of an avian migrant.

Science.gov (United States)

Nourani, Elham; Yamaguchi, Noriyuki M; Higuchi, Hiroyoshi

2017-05-17

Migratory birds can be adversely affected by climate change as they encounter its geographically uneven impacts in various stages of their life cycle. While a wealth of research is devoted to the impacts of climate change on distribution range and phenology of migratory birds, the indirect effects of climate change on optimal migratory routes and flyways, through changes in air movements, are poorly understood. Here, we predict the influence of climate change on the migratory route of a long-distant migrant using an ensemble of correlative modelling approaches, and present and future atmospheric data obtained from a regional climate model. We show that changes in wind conditions by mid-century will result in a slight shift and reduction in the suitable areas for migration of the study species, the Oriental honey-buzzard, over a critical section of its autumn journey, followed by a complete loss of this section of the traditional route by late century. Our results highlight the need for investigating the consequences of climate change-induced disturbance in wind support for long-distance migratory birds, particularly species that depend on the wind to cross ecological barriers, and those that will be exposed to longer journeys due to future range shifts. © 2017 The Author(s).

FAK/src-family dependent activation of the Ste20-like kinase SLK is required for microtubule-dependent focal adhesion turnover and cell migration.

Directory of Open Access Journals (Sweden)

Simona Wagner

2008-04-01

Full Text Available Cell migration involves a multitude of signals that converge on cytoskeletal reorganization, essential for development, immune responses and tissue repair. Using knockdown and dominant negative approaches, we show that the microtubule-associated Ste20-like kinase SLK is required for focal adhesion turnover and cell migration downstream of the FAK/c-src complex. Our results show that SLK co-localizes with paxillin, Rac1 and the microtubules at the leading edge of migrating cells and is activated by scratch wounding. SLK activation is dependent on FAK/c-src/MAPK signaling, whereas SLK recruitment to the leading edge is src-dependent but FAK independent. Our results show that SLK represents a novel focal adhesion disassembly signal.

Convergent Metabolic Specialization through Distinct Evolutionary Paths in Pseudomonas aeruginosa

DEFF Research Database (Denmark)

La Rosa, Ruggero; Johansen, Helle Krogh; Molin, Søren

2018-01-01

fibrosis (CF) infection. In this work, we investigated how and through which trajectories evolution of Pseudomonas aeruginosa occurs when migrating from the environment to the airways of CF patients, and specifically, we determined reduction of growth rate and metabolic specialization as signatures...... of adaptive evolution. We show that central metabolic pathways of three distinct Pseudomonas aeruginosa lineages coevolving within the same environment become restructured at the cost of versatility during long-term colonization. Cell physiology changes from naive to adapted phenotypes resulted in (i......) alteration of growth potential that particularly converged to a slow-growth phenotype, (ii) alteration of nutritional requirements due to auxotrophy, (iii) tailored preference for carbon source assimilation from CF sputum, (iv) reduced arginine and pyruvate fermentation processes, and (v) increased oxygen...

Turbulence investigation and reproduction for assisting downstream migrating juvenile salmonids, Part II of II: Effects of induced turbulence on behavior of juvenile salmon, 2001-2005 final report

Science.gov (United States)

Perry, R.; Farley , M.; Hansen, G.; Morse , J.; Rondorf, D.

2005-01-01

Passage through dams is a major source of mortality of anadromous juvenile salmonids because some populations must negotiate up to eight dams in Columbia and Snake rivers. Dams cause direct mortality when fish pass through turbines, but dams may also cause indirect mortality by altering migration conditions in rivers. Forebays immediately upstream of dams have decreased the water velocity of rivers and may contribute substantially to the total migration delay of juvenile salmonids. Recently, Coutant (2001a) suggested that in addition to low water velocities, lack of natural turbulence may contribute to migration delay by causing fish to lose directional cues. Coutant (2001a) further hypothesized that restoring turbulence in dam forebays may reduce migration delay by providing directional cues that allow fish to find passage routes more quickly (Coutant 2001a). Although field experiments have yielded proof of the concept of using induced turbulence to guide fish to safe passage routes, little is known about mechanisms actually causing behavioral changes. To test hypotheses about how turbulence influences movement and behavior of migrating juvenile salmonids, we conducted two types of controlled experiments at Cowlitz Falls Dam, Washington. A common measure of migration delay is the elapsed time between arrival at, and passage through, a dam. Therefore, for the first set of experiments, we tested the effect of induced turbulence on the elapsed time needed for fish to traverse through a raceway and pass over a weir at its downstream end (time trial experiment). If turbulence helps guide fish to passage routes, then fish should pass through the raceway quicker in the presence of appropriately scaled and directed turbulent cues. Second, little is known about how the physical properties of water movement provide directional cues to migrating juvenile salmonids. To examine the feasibility of guiding fish with turbulence, we tested whether directed turbulence could guide

Route churn: an analysis of low-cost carrier route continuity in Europe

NARCIS (Netherlands)

de Wit, J.G.; Zuidberg, J.

2016-01-01

Discontinuity of air routes is a subject that has been analysed in various ways. For example, the complex network approach focuses on network robustness and resilience due to route interruptions during a relatively short period. Also seasonal interruptions of air routes are a well-documented

Beyond Brainstorming: Exploring Convergence in Teams

Science.gov (United States)

Seeber, Isabella; de Vreede, Gert-Jan; Maier, Ronald; Weber, Barbara

2017-01-01

Abstract Collaborative brainstorming is often followed by a convergence activity where teams extract the most promising ideas on a useful level of detail from the brainstorming results. Contrary to the wealth of research on electronic brainstorming, there is a dearth of research on convergence. We used experimental methods for an in-depth exploration of two facilitation-based interventions in a convergence activity: attention guidance (focusing participants on procedures to execute a convergence task) and discussion encouragement (engaging participants in conversations to combine knowledge on ideas). Our findings show that both attention guidance and discussion encouragement are correlated with higher convergence quality. We argue that attention guidance’s contribution is in its support of coordination, information processing, and goal specification. Similar, we argue that discussion encouragement’s contribution is in its stimulation of idea clarification and idea combination. Contrary to past research, our findings further show that satisfaction was higher after convergence than after brainstorming. PMID:29399005

Semantic Convergence in the Bilingual Lexicon

Science.gov (United States)

Ameel, Eef; Malt, Barbara C.; Storms, Gert; Van Assche, Fons

2009-01-01

Bilinguals' lexical mappings for their two languages have been found to converge toward a common naming pattern. The present paper investigates in more detail how semantic convergence is manifested in bilingual lexical knowledge. We examined how semantic convergence affects the centers and boundaries of lexical categories for common household…

The paradox of extreme high-altitude migration in bar-headed geese Anser indicus

Science.gov (United States)

Hawkes, L. A.; Balachandran, S.; Batbayar, N.; Butler, P. J.; Chua, B.; Douglas, D. C.; Frappell, P. B.; Hou, Y.; Milsom, W. K.; Newman, S. H.; Prosser, D. J.; Sathiyaselvam, P.; Scott, G. R.; Takekawa, J. Y.; Natsagdorj, T.; Wikelski, M.; Witt, M. J.; Yan, B.; Bishop, C. M.

2013-01-01

Bar-headed geese are renowned for migratory flights at extremely high altitudes over the world's tallest mountains, the Himalayas, where partial pressure of oxygen is dramatically reduced while flight costs, in terms of rate of oxygen consumption, are greatly increased. Such a mismatch is paradoxical, and it is not clear why geese might fly higher than is absolutely necessary. In addition, direct empirical measurements of high-altitude flight are lacking. We test whether migrating bar-headed geese actually minimize flight altitude and make use of favourable winds to reduce flight costs. By tracking 91 geese, we show that these birds typically travel through the valleys of the Himalayas and not over the summits. We report maximum flight altitudes of 7290 m and 6540 m for southbound and northbound geese, respectively, but with 95 per cent of locations received from less than 5489 m. Geese travelled along a route that was 112 km longer than the great circle (shortest distance) route, with transit ground speeds suggesting that they rarely profited from tailwinds. Bar-headed geese from these eastern populations generally travel only as high as the terrain beneath them dictates and rarely in profitable winds. Nevertheless, their migration represents an enormous challenge in conditions where humans and other mammals are only able to operate at levels well below their sea-level maxima. PMID:23118436

Convergence semigroup actions: generalized quotients

Directory of Open Access Journals (Sweden)

H. Boustique

2009-10-01

Full Text Available Continuous actions of a convergence semigroup are investigated in the category of convergence spaces. Invariance properties of actions as well as properties of a generalized quotient space are presented

Globalization and Contemporary Fertility Convergence.

Science.gov (United States)

Hendi, Arun S

2017-09-01

The rise of the global network of nation-states has precipitated social transformations throughout the world. This article examines the role of political and economic globalization in driving fertility convergence across countries between 1965 and 2009. While past research has typically conceptualized fertility change as a country-level process, this study instead employs a theoretical and methodological framework that examines differences in fertility between pairs of countries over time. Convergence in fertility between pairs of countries is hypothesized to result from increased cross-country connectedness and cross-national transmission of fertility-related schemas. I investigate the impact of various cross-country ties, including ties through bilateral trade, intergovernmental organizations, and regional trade blocs, on fertility convergence. I find that globalization acts as a form of social interaction to produce fertility convergence. There is significant heterogeneity in the effects of different cross-country ties. In particular, trade with rich model countries, joint participation in the UN and UNESCO, and joining a free trade agreement all contribute to fertility convergence between countries. Whereas the prevailing focus in fertility research has been on factors producing fertility declines, this analysis highlights specific mechanisms-trade and connectedness through organizations-leading to greater similarity in fertility across countries. Globalization is a process that propels the spread of culturally laden goods and schemas impinging on fertility, which in turn produces fertility convergence.

How do en route events around the Gulf of Mexico influence landbird populations

Science.gov (United States)

Cohen, Emily B.; Barrow, Wylie C.; Buler, Jeffrey J.; Deppe, Jill L.; Farnsworth, Andrew; Marra, Peter P.; McWilliams, Scott R.; Mehlman, David W; Wilson, R. Randy; Woodrey, Mark S; Moore, Frank R.

2017-01-01

Habitats around the Gulf of Mexico (GOM) provide critical resources for Nearctic–Neotropical migratory landbirds, the majority of which travel across or around the GOM every spring and fall as they migrate between temperate breeding grounds in North America and tropical wintering grounds in the Caribbean and Central and South America. At the same time, ecosystems in the GOM are changing rapidly, with unknown consequences for migratory landbird populations, many of which are experiencing population declines. In general, the extent to which events encountered en route limit migratory bird populations is not well understood. At the same time, information from weather surveillance radar, stable isotopes, tracking, eBird, and genetic datasets is increasingly available to address many of the unanswered questions about bird populations that migrate through stopover and airspace habitats in the GOM. We review the state of the science and identify key research needs to understand the impacts of en route events around the GOM region on populations of intercontinental landbird migrants that breed in North America, including: (1) distribution, timing, and habitat associations; (2) habitat characteristics and quality; (3) migratory connectivity; and (4) threats to and current conservation status of airspace and stopover habitats. Finally, we also call for the development of unified and comprehensive long-term monitoring guidelines and international partnerships to advance our understanding of the role of habitats around the GOM in supporting migratory landbird populations moving between temperate breeding grounds and wintering grounds in Mexico, Central and South America, and the Caribbean.

Convergence of Networks

DEFF Research Database (Denmark)

Prasad, Ramjee; Ruggieri, Marina

2008-01-01

The paper focuses on the revolutionary changes that could characterise the future of networks. Those changes involve many aspects in the conceivement and exploitation of networks: architecture, services, technologies and modeling. The convergence of wired and wireless technologies along...... with the integration of system componennts and the convergence of services (e.g. communications and navigation) are only some of the elements that shape the perpsected mosaic. Authors delineate this vision, highlighting the presence of the space and stratospheric components and the related services as building block...

Hazmat Routes (National)

Data.gov (United States)

Department of Transportation — The Federal Motor Carrier Safety Administration (FMCSA) Hazardous Material Routes (NTAD) were developed using the 2004 First Edition TIGER/Line files. The routes are...

OpenMC In Situ Source Convergence Detection

Energy Technology Data Exchange (ETDEWEB)

Aldrich, Garrett Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of California, Davis, CA (United States); Dutta, Soumya [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); The Ohio State Univ., Columbus, OH (United States); Woodring, Jonathan Lee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-05-07

We designed and implemented an in situ version of particle source convergence for the OpenMC particle transport simulator. OpenMC is a Monte Carlo based-particle simulator for neutron criticality calculations. For the transport simulation to be accurate, source particles must converge on a spatial distribution. Typically, convergence is obtained by iterating the simulation by a user-settable, fixed number of steps, and it is assumed that convergence is achieved. We instead implement a method to detect convergence, using the stochastic oscillator for identifying convergence of source particles based on their accumulated Shannon Entropy. Using our in situ convergence detection, we are able to detect and begin tallying results for the full simulation once the proper source distribution has been confirmed. Our method ensures that the simulation is not started too early, by a user setting too optimistic parameters, or too late, by setting too conservative a parameter.

Quaternary tectonic evolution of the Pamir-Tian Shan convergence zone, Northwest China

Science.gov (United States)

Thompson Jobe, Jessica Ann; Li, Tao; Chen, Jie; Burbank, Douglas W.; Bufe, Aaron

2017-12-01

The Pamir-Tian Shan collision zone in the western Tarim Basin, northwest China, formed from rapid and ongoing convergence in response to the Indo-Eurasian collision. The arid landscape preserves suites of fluvial terraces crossing structures active since the late Neogene that create fault and fold scarps recording Quaternary deformation. Using geologic and geomorphic mapping, differential GPS surveys of deformed terraces, and optically stimulated luminescence dating, we create a synthesis of the active structures that delineate the timing, rate, and migration of Quaternary deformation during ongoing convergence. New deformation rates on eight faults and folds, when combined with previous studies, highlight the spatial and temporal patterns of deformation within the Pamir-Tian Shan convergence zone during the Quaternary. Terraces spanning 130 to 8 ka record deformation rates between 0.1 and 5.6 mm/yr on individual structures. In the westernmost Tarim Basin, where the Pamir and Tian Shan are already juxtaposed, the fastest rates occur on actively deforming structures at the interface of the Pamir-Tian Shan orogens. Farther east, as the separation between the Pamir-Tian Shan orogens increases, the deformation has not been concentrated on a single structure, but rather has been concurrently distributed across a zone of faults and folds in the Kashi-Atushi fold-and-thrust belt and along the NE Pamir margin, where shortening rates vary on individual structures during the Quaternary. Although numerous structures accommodate the shortening and the locus of deformation shifts during the Quaternary, the total shortening across the western Tarim Basin has remained steady and approximately matches the current geodetic rate of 6-9 mm/yr.

Genomic and cranial phenotype data support multiple modern human dispersals from Africa and a southern route into Asia.

Science.gov (United States)

Reyes-Centeno, Hugo; Ghirotto, Silvia; Détroit, Florent; Grimaud-Hervé, Dominique; Barbujani, Guido; Harvati, Katerina

2014-05-20

Despite broad consensus on Africa as the main place of origin for anatomically modern humans, their dispersal pattern out of the continent continues to be intensely debated. In extant human populations, the observation of decreasing genetic and phenotypic diversity at increasing distances from sub-Saharan Africa has been interpreted as evidence for a single dispersal, accompanied by a series of founder effects. In such a scenario, modern human genetic and phenotypic variation was primarily generated through successive population bottlenecks and drift during a rapid worldwide expansion out of Africa in the Late Pleistocene. However, recent genetic studies, as well as accumulating archaeological and paleoanthropological evidence, challenge this parsimonious model. They suggest instead a "southern route" dispersal into Asia as early as the late Middle Pleistocene, followed by a separate dispersal into northern Eurasia. Here we test these competing out-of-Africa scenarios by modeling hypothetical geographical migration routes and assessing their correlation with neutral population differentiation, as measured by genetic polymorphisms and cranial shape variables of modern human populations from Africa and Asia. We show that both lines of evidence support a multiple-dispersals model in which Australo-Melanesian populations are relatively isolated descendants of an early dispersal, whereas other Asian populations are descended from, or highly admixed with, members of a subsequent migration event.

The demographics of human and malaria movement and migration patterns in East Africa.

Science.gov (United States)

Pindolia, Deepa K; Garcia, Andres J; Huang, Zhuojie; Smith, David L; Alegana, Victor A; Noor, Abdisalan M; Snow, Robert W; Tatem, Andrew J

2013-11-05

The quantification of parasite movements can provide valuable information for control strategy planning across all transmission intensities. Mobile parasite carrying individuals can instigate transmission in receptive areas, spread drug resistant strains and reduce the effectiveness of control strategies. The identification of mobile demographic groups, their routes of travel and how these movements connect differing transmission zones, potentially enables limited resources for interventions to be efficiently targeted over space, time and populations. National population censuses and household surveys provide individual-level migration, travel, and other data relevant for understanding malaria movement patterns. Together with existing spatially referenced malaria data and mathematical models, network analysis techniques were used to quantify the demographics of human and malaria movement patterns in Kenya, Uganda and Tanzania. Movement networks were developed based on connectivity and magnitudes of flow within each country and compared to assess relative differences between regions and demographic groups. Additional malaria-relevant characteristics, such as short-term travel and bed net use, were also examined. Patterns of human and malaria movements varied between demographic groups, within country regions and between countries. Migration rates were highest in 20-30 year olds in all three countries, but when accounting for malaria prevalence, movements in the 10-20 year age group became more important. Different age and sex groups also exhibited substantial variations in terms of the most likely sources, sinks and routes of migration and malaria movement, as well as risk factors for infection, such as short-term travel and bed net use. Census and survey data, together with spatially referenced malaria data, GIS and network analysis tools, can be valuable for identifying, mapping and quantifying regional connectivities and the mobility of different demographic

Depth migration and de-migration for 3-D migration velocity analysis; Migration profondeur et demigration pour l'analyse de vitesse de migration 3D

Energy Technology Data Exchange (ETDEWEB)

Assouline, F.

2001-07-01

3-D seismic imaging of complex geologic structures requires the use of pre-stack imaging techniques, the post-stack ones being unsuitable in that case. Indeed, pre-stack depth migration is a technique which allows to image accurately complex structures provided that we have at our disposal a subsurface velocity model accurate enough. The determination of this velocity model is thus a key element for seismic imaging, and to this end, migration velocity analysis methods have met considerable interest. The SMART method is a specific migration velocity analysis method: the singularity of this method is that it does not rely on any restrictive assumptions on the complexity of the velocity model to determine. The SMART method uses a detour through the pre-stack depth migrated domain for extracting multi-offset kinematic information hardly accessible in the time domain. Once achieved the interpretation of the pre-stack depth migrated seismic data, a kinematic de-migration technique of the interpreted events enables to obtain a consistent kinematic database (i.e. reflection travel-times). Then, the inversion of these travel-times, by means of reflection tomography, allows the determination of an accurate velocity model. To be able to really image geologic structures for which the 3-D feature is predominant, we have studied the implementation of migration velocity analysis in 3-D in the context of the SMART method, and more generally, we have developed techniques allowing to overcome the intrinsic difficulties in the 3-D aspects of seismic imaging. Indeed, although formally the SMART method can be directly applied to the case of 3-D complex structures, the feasibility of its implementation requires to choose well the imaging domain. Once this choice done, it is also necessary to conceive a method allowing, via the associated de-migration, to obtain the reflection travel-times. We first consider the offset domain which constitutes, still today, the strategy most usually used

The Convergence in Spatial Tasks

Directory of Open Access Journals (Sweden)

Vladimir P. Kulagin

2013-01-01

Full Text Available The article reveals the problem of convergence of direct and inverse problems in Earth Sciences, describes the features and application of these problems, discloses analytical features of direct and inverse problems. The convergence criteria and conditions for convergence were presented. This work is supported by the Grant of the Government of the Russian Federation for support of scientific research, implemented under the supervision of leading scientists in Russian institutions of higher education in the field "Space Research and Technologies" in 2011–2013.

[Identification and sampling of people with migration background for epidemiological studies in Germany].

Science.gov (United States)

Reiss, K; Makarova, N; Spallek, J; Zeeb, H; Razum, O

2013-06-01

In 2009, 19.6% of the population of Germany either had migrated themselves or were the offspring of people with migration experience. Migrants differ from the autochthonous German population in terms of health status, health awareness and health behaviour. To further investigate the health situation of migrants in Germany, epidemiological studies are needed. Such studies can employ existing databases which provide detailed information on migration status. Otherwise, onomastic or toponomastic procedures can be applied to identify people with migration background. If migrants have to be recruited into an epidemiological study, this can be done register-based (e. g., data from registration offices or telephone lists), based on residential location (random-route or random-walk procedure), via snowball sampling (e. g., through key persons) or via settings (e. g., school entry examination). An oversampling of people with migration background is not sufficient to avoid systematic bias in the sample due to non-participation. Additional measures have to be taken to increase access and raise participation rates. Personal contacting, multilingual instruments, multilingual interviewers and extensive public relations increase access and willingness to participate. Empirical evidence on 'successful' recruitment strategies for studies with migrants is still lacking in epidemiology and health sciences in Germany. The choice of the recruitment strategy as well as the measures to raise accessibility and willingness to participate depend on the available resources, the research question and the specific migrant target group. © Georg Thieme Verlag KG Stuttgart · New York.

Ocean-wide Drivers of Migration Strategies and Their Influence on Population Breeding Performance in a Declining Seabird.

Science.gov (United States)

Fayet, Annette L; Freeman, Robin; Anker-Nilssen, Tycho; Diamond, Antony; Erikstad, Kjell E; Fifield, Dave; Fitzsimmons, Michelle G; Hansen, Erpur S; Harris, Mike P; Jessopp, Mark; Kouwenberg, Amy-Lee; Kress, Steve; Mowat, Stephen; Perrins, Chris M; Petersen, Aevar; Petersen, Ib K; Reiertsen, Tone K; Robertson, Gregory J; Shannon, Paula; Sigurðsson, Ingvar A; Shoji, Akiko; Wanless, Sarah; Guilford, Tim

2017-12-18

Which factors shape animals' migration movements across large geographical scales, how different migratory strategies emerge between populations, and how these may affect population dynamics are central questions in the field of animal migration [1] that only large-scale studies of migration patterns across a species' range can answer [2]. To address these questions, we track the migration of 270 Atlantic puffins Fratercula arctica, a red-listed, declining seabird, across their entire breeding range. We investigate the role of demographic, geographical, and environmental variables in driving spatial and behavioral differences on an ocean-basin scale by measuring puffins' among-colony differences in migratory routes and day-to-day behavior (estimated with individual daily activity budgets and energy expenditure). We show that competition and local winter resource availability are important drivers of migratory movements, with birds from larger colonies or with poorer local winter conditions migrating further and visiting less-productive waters; this in turn led to differences in flight activity and energy expenditure. Other behavioral differences emerge with latitude, with foraging effort and energy expenditure increasing when birds winter further north in colder waters. Importantly, these ocean-wide migration patterns can ultimately be linked with breeding performance: colony productivity is negatively associated with wintering latitude, population size, and migration distance, which demonstrates the cost of competition and migration on future breeding and the link between non-breeding and breeding periods. Our results help us to understand the drivers of animal migration and have important implications for population dynamics and the conservation of migratory species. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impacts of Interannual Ocean Circulation Variability on Japanese Eel Larval Migration in the Western North Pacific Ocean.

Directory of Open Access Journals (Sweden)

Yu-Lin Chang

Full Text Available The Japanese eel larvae hatch near the West Mariana Ridge seamount chain and travel through the North Equatorial Current (NEC, the Kuroshio, and the Subtropical Countercurrent (STCC region during their shoreward migration toward East Asia. The interannual variability of circulation over the subtropical and tropical regions of the western North Pacific Ocean is affected by the Philippines-Taiwan Oscillation (PTO. This study examines the effect of the PTO on the Japanese eel larval migration routes using a three-dimensional (3D particle tracking method, including vertical and horizontal swimming behavior. The 3D circulation and hydrography used for particle tracking are from the ocean circulation reanalysis produced by the Japan Coastal Ocean Predictability Experiment 2 (JCOPE2. Our results demonstrate that bifurcation of the NEC and the strength and spatial variation of the Kuroshio affect the distribution and migration of eel larvae. During the positive phase of PTO, more virtual eels ("v-eels" can enter the Kuroshio to reach the south coast of Japan and more v-eels reach the South China Sea through the Luzon Strait; the stronger and more offshore swing of the Kuroshio in the East China Sea leads to fewer eels entering the East China Sea and the onshore movement of the Kuroshio to the south of Japan brings the eels closer to the Japanese coast. Significant differences in eel migration routes and distributions regulated by ocean circulation in different PTO phases can also affect the otolith increment. The estimated otolith increment suggests that eel age tends to be underestimated after six months of simulation due to the cooler lower layer temperature. Underestimation is more significant in the positive PTO years due to the wide distribution in higher latitudes than in the negative PTO years.

Impacts of Interannual Ocean Circulation Variability on Japanese Eel Larval Migration in the Western North Pacific Ocean.

Science.gov (United States)

Chang, Yu-Lin; Sheng, Jinyu; Ohashi, Kyoko; Béguer-Pon, Mélanie; Miyazawa, Yasumasa

2015-01-01

The Japanese eel larvae hatch near the West Mariana Ridge seamount chain and travel through the North Equatorial Current (NEC), the Kuroshio, and the Subtropical Countercurrent (STCC) region during their shoreward migration toward East Asia. The interannual variability of circulation over the subtropical and tropical regions of the western North Pacific Ocean is affected by the Philippines-Taiwan Oscillation (PTO). This study examines the effect of the PTO on the Japanese eel larval migration routes using a three-dimensional (3D) particle tracking method, including vertical and horizontal swimming behavior. The 3D circulation and hydrography used for particle tracking are from the ocean circulation reanalysis produced by the Japan Coastal Ocean Predictability Experiment 2 (JCOPE2). Our results demonstrate that bifurcation of the NEC and the strength and spatial variation of the Kuroshio affect the distribution and migration of eel larvae. During the positive phase of PTO, more virtual eels ("v-eels") can enter the Kuroshio to reach the south coast of Japan and more v-eels reach the South China Sea through the Luzon Strait; the stronger and more offshore swing of the Kuroshio in the East China Sea leads to fewer eels entering the East China Sea and the onshore movement of the Kuroshio to the south of Japan brings the eels closer to the Japanese coast. Significant differences in eel migration routes and distributions regulated by ocean circulation in different PTO phases can also affect the otolith increment. The estimated otolith increment suggests that eel age tends to be underestimated after six months of simulation due to the cooler lower layer temperature. Underestimation is more significant in the positive PTO years due to the wide distribution in higher latitudes than in the negative PTO years.

Southward autumn migration of waterfowl facilitates cross-continental transmission of the highly pathogenic avian influenza H5N1 virus

Science.gov (United States)

Xu, Yanjie; Gong, Peng; Wielstra, Ben; Si, Yali

2016-08-01

The highly pathogenic avian influenza subtype H5N1 (HPAI H5N1) is a worldwide zoonotic infectious disease, threatening humans, poultry and wild birds. The role of wild birds in the spread of HPAI H5N1 has previously been investigated by comparing disease spread patterns with bird migration routes. However, the different roles that the southward autumn and northward spring migration might play in virus transmission have hardly been explored. Using direction analysis, we analyze HPAI H5N1 transmission directions and angular concentration of currently circulating viral clades, and compare these with waterfowl seasonal migration directions along major waterfowl flyways. Out of 22 HPAI H5N1 transmission directions, 18 had both a southward direction and a relatively high concentration. Differences between disease transmission and waterfowl migration directions were significantly smaller for autumn than for spring migration. The four northward transmission directions were found along Asian flyways, where the initial epicenter of the virus was located. We suggest waterfowl first picked up the virus from East Asia, then brought it to the north via spring migration, and then spread it to other parts of world mainly by autumn migration. We emphasize waterfowl autumn migration plays a relatively important role in HPAI H5N1 transmission compared to spring migration.

Spring migration of Northern Pintails from Texas and New Mexico, USA

Science.gov (United States)

Haukos, D.A.; Miller, M.R.; Orthmeyer, D.L.; Takekawa, John Y.; Fleskes, J.P.; Casazza, Michael L.; Perry, W.M.; Moon, J.A.

2006-01-01

We used satellite transmitters (platform transmitting terminals or PTTs) during 2002 and 2003 to document spring migration timing, routes, stopover sites, and nesting sites of adult female Northern Pintails (Anas acuta) from major wintering areas of the Gulf Coast (N = 20) and Playa Lakes Regions (PLR, N = 20) in Texas, and the Middle Rio Grande Valley, New Mexico (MRGV, N = 15). Some Pintails tagged in the MRGV continued movements into Mexico. Poor winter survival or PTT failure reduced sample size to 15 for PLR Pintails, 5 for Gulf Coast Pintails, and 11 for MRGV Pintails. Apparent winter survival was 66% lower for Texas Gulf Coast PTT-tagged Pintails than for those from the PLR and MRGV. Pintails from each area used different routes to their respective breeding grounds. PTT-tagged Pintails from the MRGV followed the Rio Grande Valley north to southern Colorado, before traveling on to the Dakotas and Canada or traveled northeast and joined the migration of PLR Pintails in Texas or Kansas. The latter made initial stops in Kansas, Nebraska, Colorado, or the Dakotas. Gulf Coast Pintails traveled through north-central Oklahoma or central Kansas. Pintails that had stopped first in Kansas or Nebraska tended to settle to nest in the United States. Wetland availability in the Prairie Pothole Region of the Northern Great Plains influenced nesting destinations of PTT-tagged Pintails, but individuals settled across a wide swath of northern North America. We did not detect any consistently-used spring staging areas. Therefore, negative impacts to any of the marked populations, or their wetland habitats, may have continental implications.

Indoor Semantic Modelling for Routing: The Two-Level Routing Approach for Indoor Navigation

Directory of Open Access Journals (Sweden)

Liu Liu

2017-11-01

Full Text Available Humans perform many activities indoors and they show a growing need for indoor navigation, especially in unfamiliar buildings such as airports, museums and hospitals. Complexity of such buildings poses many challenges for building managers and visitors. Indoor navigation services play an important role in supporting these indoor activities. Indoor navigation covers extensive topics such as: 1 indoor positioning and localization; 2 indoor space representation for navigation model generation; 3 indoor routing computation; 4 human wayfinding behaviours; and 5 indoor guidance (e.g., textual directories. So far, a large number of studies of pedestrian indoor navigation have presented diverse navigation models and routing algorithms/methods. However, the major challenge is rarely referred to: how to represent the complex indoor environment for pedestrians and conduct routing according to the different roles and sizes of users. Such complex buildings contain irregular shapes, large open spaces, complicated obstacles and different types of passages. A navigation model can be very complicated if the indoors are accurately represented. Although most research demonstrates feasible indoor navigation models and related routing methods in regular buildings, the focus is still on a general navigation model for pedestrians who are simplified as circles. In fact, pedestrians represent different sizes, motion abilities and preferences (e.g., described in user profiles, which should be reflected in navigation models and be considered for indoor routing (e.g., relevant Spaces of Interest and Points of Interest. In order to address this challenge, this thesis proposes an innovative indoor modelling and routing approach – two-level routing. It specially targets the case of routing in complex buildings for distinct users. The conceptual (first level uses general free indoor spaces: this is represented by the logical network whose nodes represent the spaces and edges

Multihop Wireless Networks Opportunistic Routing

CERN Document Server

Zeng, Kai; Li, Ming

2011-01-01

This book provides an introduction to opportunistic routing an emerging technology designed to improve the packet forwarding reliability, network capacity and energy efficiency of multihop wireless networks This book presents a comprehensive background to the technological challenges lying behind opportunistic routing. The authors cover many fundamental research issues for this new concept, including the basic principles, performance limit and performance improvement of opportunistic routing compared to traditional routing, energy efficiency and distributed opportunistic routing protocol desig

Research for annual travel-route changes of reindeer living around the Arctic Circle using satellite remote sensing

Science.gov (United States)

Suzuki, G.; Sakka, T.; Tashiro, T.; Kawamata, H.; Tatsuzawa, S.; Naruse, N.; Takahashi, Y.

2017-12-01

For a long time, nomads living in the Arctic Circle around Siberia have been making a living by hunting reindeer traditionally. Wild reindeer have a recurrent migration every year, however, the travel-route of reindeer has been changing recently, so the nomads cannot expect the route in their traditional experience. To support them, one of authors (Tatsuzawa) investigated the route by installing GPS transmitter to some reindeer. The reason of the changing route, however, remain unclear. Previous works indicated that the reason of changing the route must be a global warming, forest fires, thunders, and floods, but they only discuss only on the basis of measurements in specific area. The purpose of this study is to research why the arctic reindeer alter the travel route annually through 1) the annual change of vegetation (NDVI: normalized difference vegetation index) in reindeer ground, and through 2) the annual change of soil water content (mNDWI: modified normalized difference water index) which can be reflected precipitation near Lena river. First, we analyzed NDVI using MODIS images that can be observed over a wide area, filmed in July and August; the reindeer started to travel. We have compared the seasonal changes of the NDVI images with the trace obtained by GPS data from 2010 to 2012. Although NDVI images in July showed similar numerical values in every year, the satellite images taken at August 29 is annually different; NDVI values become lower (0.5 or less) when the reindeer travel to the north area in winter. This suggests that reindeer move to secure enough food in the end of summer. In contrast, mNDWI becomes high when the reindeer travel to the north area. The annual changes of the route may be related to the amount of rainfall.

Migration of rice planthoppers and their vectored re-emerging and novel rice viruses in East Asia.

Science.gov (United States)

Otuka, Akira

2013-10-28

This review examines recent studies of the migration of three rice planthoppers, Laodelphax striatellus, Sogatella furcifera, and Nilaparvata lugens, in East Asia. Laodelphax striatellus has recently broken out in Jiangsu province, eastern China. The population density in the province started to increase in the early 2000s and peaked in 2004. In 2005, Rice stripe virus (RSV) viruliferous rate of L. striatellus peaked at 31.3%. Since then, rice stripe disease spread severely across the whole province. Due to the migration of the RSV vectors, the rice stripe disease spread to neighboring countries Japan and Korea. An overseas migration of L. striatellus that occurred in 2008 was analyzed, when a slow-moving cold vortex, a type of low pressure system, reached western Japan from Jiangsu, carrying the insects into Japan. Subsequently the rice stripe diseases struck these areas in Japan severely. In Korea, similar situations occurred in 2009, 2011, and 2012. Their migration sources were also estimated to be in Jiangsu by backward trajectory analysis. Rice black-streaked dwarf virus, whose vector is L. striatellus, has recently re-emerged in eastern China, and the evidence for overseas migrations of the virus, just like the RSV's migrations, has been given. A method of predicting the overseas migration of L. striatellus has been developed by Japanese, Chinese, and Korean institutes. An evaluation of the prediction showed that this method properly predicted migration events that occurred in East Asia from 2008 to 2011. Southern rice black-streaked dwarf virus (SRBSDV) was first found in Guangdong province. Its vector is S. furcifera. An outbreak of SRBSDV occurred in southern China in 2009 and spread to Vietnam the same year. This disease and virus were also found in Japan in 2010. The epidemic triggered many migration studies to investigate concrete spring-summer migration routes in China, and the addition of migration sources for early arrivals in Guangdong and Guangxi

Statistical convergence on intuitionistic fuzzy normed spaces

International Nuclear Information System (INIS)

Karakus, S.; Demirci, K.; Duman, O.

2008-01-01

Saadati and Park [Saadati R, Park JH, Chaos, Solitons and Fractals 2006;27:331-44] has recently introduced the notion of intuitionistic fuzzy normed space. In this paper, we study the concept of statistical convergence on intuitionistic fuzzy normed spaces. Then we give a useful characterization for statistically convergent sequences. Furthermore, we display an example such that our method of convergence is stronger than the usual convergence on intuitionistic fuzzy normed spaces

Constraints on the magnitude of the deglacial migration of the ITCZ in the Central Equatorial Pacific Ocean

Science.gov (United States)

Reimi, Maria A.; Marcantonio, Franco

2016-11-01

Accurate paleo-latitudinal reconstructions of the Intertropical Convergence Zone (ITCZ) are necessary for understanding tropical hydroclimate and atmospheric circulation. Paleoclimate models and records suggest that as global temperatures increase, the ITCZ should migrate towards the warmer hemisphere. Many uncertainties remain regarding the magnitude of this migration, and few studies have focused on the Central Equatorial Pacific (CEP). Here, we use eolian dust records recovered from three locations in the CEP to address changes in dust provenance across the paleo ITCZ since the last glacial maximum (LGM). Radiogenic isotope compositions of Nd and Pb show that dust delivered to the CEP was sourced mainly from two regions: East Asia and South America. From these data we deduced that since Marine Oxygen Isotope Stage 2 (MIS2) the ITCZ has migrated north to its modern position, being displaced by as much as 7°, to as little as 2.5°. We find that the ITCZ migrated further north during the early Holocene (∼9 kyr), reaching its position furthest north during the mid-Holocene warm interval (∼7 kyr), based on an increase in South American dust at the northernmost sites.

Cultura da Convergência

Directory of Open Access Journals (Sweden)

Rogério Christofoletti

2008-12-01

Full Text Available Três idéias já seriam suficientes para que a leitura de “Culturada Convergência”, de Henry Jenkins, interessasse a jornalistas epesquisadores da área: a convergência midiática como um processo cultural; o fortalecimento de uma economia afetiva que orienta consumidores de bens simbólicos e criadores midiáticos; a expansão de formas narrativas transmidiáticas.

Metabolic routing of dietary nutrients in birds: effects of diet quality and macronutrient composition revealed using stable isotopes.

Science.gov (United States)

Podlesak, David W; McWilliams, Scott R

2006-01-01

During fall migration many songbirds switch from consuming primarily insects to consuming mostly fruit. Fruits with more carbohydrates and less protein may be sufficient to rebuild expended fat stores, but such fruits may be inadequate to replace catabolized protein. We manipulated the concentrations and isotopic signatures of macronutrients in diets fed to birds to study the effects of diet quality on metabolic routing of dietary nutrients. We estimated that approximately 45% and 75%, respectively, of the carbon in proteinaceous tissue of birds switched to high- or low-protein diets came from nonprotein dietary sources. In contrast, we estimated that approximately 100% and 20%-80%, respectively, of the nitrogen in proteinaceous tissues of birds switched to high- or low-protein diets was attributable to dietary protein. Thus, the routing and assimilation of dietary carbon and nitrogen differed depending on diet composition. As a result, delta (15)N of tissues collected from wild animals that consume high-quality diets may reliably indicate the dietary protein source, whereas delta (13)C of these same tissues is likely the product of metabolic routing of carbon from several macronutrients. These results have implications for how isotopic discrimination is best estimated and how we can study macronutrient routing in wild animals.

Understanding individual routing behaviour.

Science.gov (United States)

Lima, Antonio; Stanojevic, Rade; Papagiannaki, Dina; Rodriguez, Pablo; González, Marta C

2016-03-01

Knowing how individuals move between places is fundamental to advance our understanding of human mobility (González et al. 2008 Nature 453, 779-782. (doi:10.1038/nature06958)), improve our urban infrastructure (Prato 2009 J. Choice Model. 2, 65-100. (doi:10.1016/S1755-5345(13)70005-8)) and drive the development of transportation systems. Current route-choice models that are used in transportation planning are based on the widely accepted assumption that people follow the minimum cost path (Wardrop 1952 Proc. Inst. Civ. Eng. 1, 325-362. (doi:10.1680/ipeds.1952.11362)), despite little empirical support. Fine-grained location traces collected by smart devices give us today an unprecedented opportunity to learn how citizens organize their travel plans into a set of routes, and how similar behaviour patterns emerge among distinct individual choices. Here we study 92 419 anonymized GPS trajectories describing the movement of personal cars over an 18-month period. We group user trips by origin-destination and we find that most drivers use a small number of routes for their routine journeys, and tend to have a preferred route for frequent trips. In contrast to the cost minimization assumption, we also find that a significant fraction of drivers' routes are not optimal. We present a spatial probability distribution that bounds the route selection space within an ellipse, having the origin and the destination as focal points, characterized by high eccentricity independent of the scale. While individual routing choices are not captured by path optimization, their spatial bounds are similar, even for trips performed by distinct individuals and at various scales. These basic discoveries can inform realistic route-choice models that are not based on optimization, having an impact on several applications, such as infrastructure planning, routing recommendation systems and new mobility solutions. © 2016 The Author(s).

Convergent systems vs. incremental stability

NARCIS (Netherlands)

Rüffer, B.S.; Wouw, van de N.; Mueller, M.

2013-01-01

Two similar stability notions are considered; one is the long established notion of convergent systems, the other is the younger notion of incremental stability. Both notions require that any two solutions of a system converge to each other. Yet these stability concepts are different, in the sense

Regional Convergence and Sustainable Development in China

Directory of Open Access Journals (Sweden)

Fang Yang

2016-01-01

Full Text Available Based on the convergence theory of economic growth, this paper extends this concept to the human development index and carries out an empirical analysis of regional development in China between 1997 and 2006. Our research shows that the conditional convergence has been identified. Investment in fixed assets, government expenditure on education, health and infrastructure construction have positive effects on regional convergence of social development. Population weighted analysis of human development index provides support for weak convergence amongst provinces. Analysis of dynamics of regional distribution reveals the club convergence, which indicate two different convergence states. Central China is in the shade and lags behind, giving rise to the so-called “central downfall”. To solve this problem, the “Rise of Central China” Plan is necessary to promote the connection between coastal and inland regions of China and reduce the regional development gap.

Fate of chlorinated fatty acids in migrating sockeye salmon and their transfer to arctic grayling

DEFF Research Database (Denmark)

Mu, Huiling; Ewald, G.; Nilsson, E.

2004-01-01

To investigate whether biotransport constitutes an entry route into pristine ecosystems for nonpersistent, nonvolatile xenobiotic compounds, extractable organically bound halogen in sockeye salmon (Oncorhynchus nerka) from Alaska was determined before and after spawning migration. The major...... organohalogen compounds in the salmon were halogenated fatty acids, predominantly chlorinated species that accounted for up to 35% of the extractable, organically bound chlorine (EOCl) in the fish tissues. The amount of chlorinated fatty acids in the salmon muscle decreased as a result of spawning migration....... The decrease was correlated with that of triacylglycerols in the salmon muscle, indicating the chlorinated fatty acids to be mobilized and metabolized to approximately the same extent as the other fatty acids. Chlorinated fatty acids were also transferred to the maturing roe in a manner similar...

Convergence as conditionant for Media Regulation

Directory of Open Access Journals (Sweden)

Othon Jambeiro

2011-01-01

Full Text Available Convergence comprises a combination of interlinked and interdependent transformations, of technological, industrial, commercial, cultural and social nature, which affect communication regulation. Customers, at their time, turned also convergent, involved in an intense participative culture, which is too, from the point of view of its social and geographical range, thanks to convergence, more and more extense. Instead of passive consumers of media and information and communication services, we have now active and socially connected consumers, no more readers/spectators/listeners, but noisy activists and publishers. To understand this phenomenon is essential to discern a regulatory frame suitable for it. This paper tries to define convergence and to discuss its consequences.

Cultura da Convergência

Directory of Open Access Journals (Sweden)

Rogério Christofoletti

2008-12-01

Full Text Available Três idéias já seriam suficientes para que a leitura de “Cultura da Convergência”, de Henry Jenkins, interessasse a jornalistas e pesquisadores da área: a convergência midiática como um processo cultural; o fortalecimento de uma economia afetiva que orienta consumidores de bens simbólicos e criadores midiáticos; a expansão de formas narrativas transmidiáticas.

Convergence of barycentric coordinates to barycentric kernels

KAUST Repository

Kosinka, Jiří

2016-02-12

We investigate the close correspondence between barycentric coordinates and barycentric kernels from the point of view of the limit process when finer and finer polygons converge to a smooth convex domain. We show that any barycentric kernel is the limit of a set of barycentric coordinates and prove that the convergence rate is quadratic. Our convergence analysis extends naturally to barycentric interpolants and mappings induced by barycentric coordinates and kernels. We verify our theoretical convergence results numerically on several examples.

Convergence of barycentric coordinates to barycentric kernels

KAUST Repository

Kosinka, Jiří ; Barton, Michael

2016-01-01

We investigate the close correspondence between barycentric coordinates and barycentric kernels from the point of view of the limit process when finer and finer polygons converge to a smooth convex domain. We show that any barycentric kernel is the limit of a set of barycentric coordinates and prove that the convergence rate is quadratic. Our convergence analysis extends naturally to barycentric interpolants and mappings induced by barycentric coordinates and kernels. We verify our theoretical convergence results numerically on several examples.

Modeling Bird Migration under Climate Change: A Mechanistic Approach

Science.gov (United States)

Smith, James A.

2009-01-01

How will migrating birds respond to changes in the environment under climate change? What are the implications for migratory success under the various accelerated climate change scenarios as forecast by the Intergovernmental Panel on Climate Change? How will reductions or increased variability in the number or quality of wetland stop-over sites affect migratory bird species? The answers to these questions have important ramifications for conservation biology and wildlife management. Here, we describe the use of continental scale simulation modeling to explore how spatio-temporal changes along migratory flyways affect en-route migration success. We use an individually based, biophysical, mechanistic, bird migration model to simulate the movement of shorebirds in North America as a tool to study how such factors as drought and wetland loss may impact migratory success and modify migration patterns. Our model is driven by remote sensing and climate data and incorporates important landscape variables. The energy budget components of the model include resting, foraging, and flight, but presently predation is ignored. Results/Conclusions We illustrate our model by studying the spring migration of sandpipers through the Great Plains to their Arctic breeding grounds. Why many species of shorebirds have shown significant declines remains a puzzle. Shorebirds are sensitive to stop-over quality and spacing because of their need for frequent refueling stops and their opportunistic feeding patterns. We predict bird "hydrographs that is, stop-over frequency with latitude, that are in agreement with the literature. Mean stop-over durations predicted from our model for nominal cases also are consistent with the limited, but available data. For the shorebird species simulated, our model predicts that shorebirds exhibit significant plasticity and are able to shift their migration patterns in response to changing drought conditions. However, the question remains as to whether this

SAFEBIKE: A Bike-sharing Route Recommender with Availability Prediction and Safe Routing

OpenAIRE

Zhong, Weisheng; Chen, Fanglan; Fu, Kaiqun; Lu, Chang-Tien

2017-01-01

This paper presents SAFEBIKE, a novel route recommendation system for bike-sharing service that utilizes station information to infer the number of available bikes in dock and recommend bike routes according to multiple factors such as distance and safety level. The system consists of a station level availability predictor that predicts bikes and docks amount at each station, and an efficient route recommendation service that considers safety and bike/dock availability factors. It targets use...

Personal continuous route pattern mining

Institute of Scientific and Technical Information of China (English)

Qian YE; Ling CHEN; Gen-cai CHEN

2009-01-01

In the daily life, people often repeat regular routes in certain periods. In this paper, a mining system is developed to find the continuous route patterns of personal past trips. In order to count the diversity of personal moving status, the mining system employs the adaptive GPS data recording and five data filters to guarantee the clean trips data. The mining system uses a client/server architecture to protect personal privacy and to reduce the computational load. The server conducts the main mining procedure but with insufficient information to recover real personal routes. In order to improve the scalability of sequential pattern mining, a novel pattern mining algorithm, continuous route pattern mining (CRPM), is proposed. This algorithm can tolerate the different disturbances in real routes and extract the frequent patterns. Experimental results based on nine persons' trips show that CRPM can extract more than two times longer route patterns than the traditional route pattern mining algorithms.

Δim-lacunary statistical convergence of order α

Science.gov (United States)

Altınok, Hıfsı; Et, Mikail; Işık, Mahmut

2018-01-01

The purpose of this work is to introduce the concepts of Δim-lacunary statistical convergence of order α and lacunary strongly (Δim,p )-convergence of order α. We establish some connections between lacunary strongly (Δim,p )-convergence of order α and Δim-lacunary statistical convergence of order α. It is shown that if a sequence is lacunary strongly (Δim,p )-summable of order α then it is Δim-lacunary statistically convergent of order α.

Modified artificial bee colony for the vehicle routing problems with time windows.

Science.gov (United States)

Alzaqebah, Malek; Abdullah, Salwani; Jawarneh, Sana

2016-01-01

The natural behaviour of the honeybee has attracted the attention of researchers in recent years and several algorithms have been developed that mimic swarm behaviour to solve optimisation problems. This paper introduces an artificial bee colony (ABC) algorithm for the vehicle routing problem with time windows (VRPTW). A Modified ABC algorithm is proposed to improve the solution quality of the original ABC. The high exploration ability of the ABC slows-down its convergence speed, which may due to the mechanism used by scout bees in replacing abandoned (unimproved) solutions with new ones. In the Modified ABC a list of abandoned solutions is used by the scout bees to memorise the abandoned solutions, then the scout bees select a solution from the list based on roulette wheel selection and replace by a new solution with random routs selected from the best solution. The performance of the Modified ABC is evaluated on Solomon benchmark datasets and compared with the original ABC. The computational results demonstrate that the Modified ABC outperforms the original ABC also produce good solutions when compared with the best-known results in the literature. Computational investigations show that the proposed algorithm is a good and promising approach for the VRPTW.

Increasing dominance of IT in ICT convergence

DEFF Research Database (Denmark)

Henten, Anders; Tadayoni, Reza

The aim of the paper is to examine the increasing dominance of IT companies in the converging ICT industry and, on the basis of this development, to contribute to extending the theoretical understanding of market and industry convergence in the ICT area.......The aim of the paper is to examine the increasing dominance of IT companies in the converging ICT industry and, on the basis of this development, to contribute to extending the theoretical understanding of market and industry convergence in the ICT area....

Examining speed versus selection in connectivity models using elk migration as an example

Science.gov (United States)

Brennan, Angela; Hanks, Ephraim M.; Merkle, Jerod A.; Cole, Eric K.; Dewey, Sarah R.; Courtemanch, Alyson B.; Cross, Paul C.

2018-01-01

ContextLandscape resistance is vital to connectivity modeling and frequently derived from resource selection functions (RSFs). RSFs estimate relative probability of use and tend to focus on understanding habitat preferences during slow, routine animal movements (e.g., foraging). Dispersal and migration, however, can produce rarer, faster movements, in which case models of movement speed rather than resource selection may be more realistic for identifying habitats that facilitate connectivity.ObjectiveTo compare two connectivity modeling approaches applied to resistance estimated from models of movement rate and resource selection.MethodsUsing movement data from migrating elk, we evaluated continuous time Markov chain (CTMC) and movement-based RSF models (i.e., step selection functions [SSFs]). We applied circuit theory and shortest random path (SRP) algorithms to CTMC, SSF and null (i.e., flat) resistance surfaces to predict corridors between elk seasonal ranges. We evaluated prediction accuracy by comparing model predictions to empirical elk movements.ResultsAll connectivity models predicted elk movements well, but models applied to CTMC resistance were more accurate than models applied to SSF and null resistance. Circuit theory models were more accurate on average than SRP models.ConclusionsCTMC can be more realistic than SSFs for estimating resistance for fast movements, though SSFs may demonstrate some predictive ability when animals also move slowly through corridors (e.g., stopover use during migration). High null model accuracy suggests seasonal range data may also be critical for predicting direct migration routes. For animals that migrate or disperse across large landscapes, we recommend incorporating CTMC into the connectivity modeling toolkit.

Strategic business transformation through technology convergence

DEFF Research Database (Denmark)

Agarwal, Nivedita; Brem, Alexander

2015-01-01

-time intelligence. This paper presents the case of General Electric (GE) and studies the various transitional phases and transformation dimensions that GE is experiencing, to manage this technology convergence. The evaluation of GE's experience indicates that convergence-related business transformation is nonlinear......Technology adoption is crucial for an organisation to remain competitive in the marketplace. Traditionally, two technologies - operational technology (OT) and information technology (IT) - have operated independently from one another; however, technological advancements that businesses...... are experiencing have increased the overlap and convergence of these two areas. Industrial organisations are investing heavily in the integration and alignment of these technologies and expect to benefit in several ways from this convergence, such as through increased productivity, reduction in cost, and real...

Fixed mobile convergence handbook

CERN Document Server

Ahson, Syed A

2010-01-01

From basic concepts to future directions, this handbook provides technical information on all aspects of fixed-mobile convergence (FMC). The book examines such topics as integrated management architecture, business trends and strategic implications for service providers, personal area networks, mobile controlled handover methods, SIP-based session mobility, and supervisory and notification aggregator service. Case studies are used to illustrate technical and systematic implementation of unified and rationalized internet access by fixed-mobile network convergence. The text examines the technolo

A Globally Convergent Matrix-Free Method for Constrained Equations and Its Linear Convergence Rate

Directory of Open Access Journals (Sweden)

Min Sun

2014-01-01

Full Text Available A matrix-free method for constrained equations is proposed, which is a combination of the well-known PRP (Polak-Ribière-Polyak conjugate gradient method and the famous hyperplane projection method. The new method is not only derivative-free, but also completely matrix-free, and consequently, it can be applied to solve large-scale constrained equations. We obtain global convergence of the new method without any differentiability requirement on the constrained equations. Compared with the existing gradient methods for solving such problem, the new method possesses linear convergence rate under standard conditions, and a relax factor γ is attached in the update step to accelerate convergence. Preliminary numerical results show that it is promising in practice.

"Nanoselves": NBIC and the Culture of Convergence

Science.gov (United States)

Venkatesan, Priya

2010-01-01

The subject of this essay is NBIC convergence (nanotechnology, biotechnology, information technology and cognitive science convergence). NBIC convergence is a recurring trope that is dominated by the paradigm of integration of the sciences. It is largely influenced by the considerations of social and economic impact, and it assumes positivism in…

Sectoral Energy, and Labour, Productivity Convergence

International Nuclear Information System (INIS)

Mulder, P.; De Groot, H.L.F.

2007-01-01

This paper empirically investigates the development of cross-country differences in energy- and labour productivity. The analysis is performed at a detailed sectoral level for 14 OECD countries, covering the period 1970-1997. A ρ-convergence analysis reveals that the development over time of the cross-country variation in productivity performance differs across sectors as well as across different levels of aggregation. Both patterns of convergence as well as divergence are found. Cross-country variation of productivity levels is typically larger for energy than for labour. A β-convergence analysis provides support for the hypothesis that in most sectors lagging countries tend to catch up with technological leaders, in particular in terms of energy productivity. Moreover, the results show that convergence is conditional, meaning that productivity levels converge to country-specific steady states. Energy prices and wages are shown to positively affect energy- and labour-productivity growth, respectively. We also find evidence for the importance of economies of scale, whereas the investment share, openness and specialization play only a modest role in explaining cross-country variation in energy- and labour-productivity growth

Class network routing

Science.gov (United States)

Bhanot, Gyan [Princeton, NJ; Blumrich, Matthias A [Ridgefield, CT; Chen, Dong [Croton On Hudson, NY; Coteus, Paul W [Yorktown Heights, NY; Gara, Alan G [Mount Kisco, NY; Giampapa, Mark E [Irvington, NY; Heidelberger, Philip [Cortlandt Manor, NY; Steinmacher-Burow, Burkhard D [Mount Kisco, NY; Takken, Todd E [Mount Kisco, NY; Vranas, Pavlos M [Bedford Hills, NY

2009-09-08

Class network routing is implemented in a network such as a computer network comprising a plurality of parallel compute processors at nodes thereof. Class network routing allows a compute processor to broadcast a message to a range (one or more) of other compute processors in the computer network, such as processors in a column or a row. Normally this type of operation requires a separate message to be sent to each processor. With class network routing pursuant to the invention, a single message is sufficient, which generally reduces the total number of messages in the network as well as the latency to do a broadcast. Class network routing is also applied to dense matrix inversion algorithms on distributed memory parallel supercomputers with hardware class function (multicast) capability. This is achieved by exploiting the fact that the communication patterns of dense matrix inversion can be served by hardware class functions, which results in faster execution times.

mizuRoute version 1: A river network routing tool for a continental domain water resources applications

Science.gov (United States)

Mizukami, Naoki; Clark, Martyn P.; Sampson, Kevin; Nijssen, Bart; Mao, Yixin; McMillan, Hilary; Viger, Roland; Markstrom, Steven; Hay, Lauren E.; Woods, Ross; Arnold, Jeffrey R.; Brekke, Levi D.

2016-01-01

This paper describes the first version of a stand-alone runoff routing tool, mizuRoute. The mizuRoute tool post-processes runoff outputs from any distributed hydrologic model or land surface model to produce spatially distributed streamflow at various spatial scales from headwater basins to continental-wide river systems. The tool can utilize both traditional grid-based river network and vector-based river network data. Both types of river network include river segment lines and the associated drainage basin polygons, but the vector-based river network can represent finer-scale river lines than the grid-based network. Streamflow estimates at any desired location in the river network can be easily extracted from the output of mizuRoute. The routing process is simulated as two separate steps. First, hillslope routing is performed with a gamma-distribution-based unit-hydrograph to transport runoff from a hillslope to a catchment outlet. The second step is river channel routing, which is performed with one of two routing scheme options: (1) a kinematic wave tracking (KWT) routing procedure; and (2) an impulse response function – unit-hydrograph (IRF-UH) routing procedure. The mizuRoute tool also includes scripts (python, NetCDF operators) to pre-process spatial river network data. This paper demonstrates mizuRoute's capabilities to produce spatially distributed streamflow simulations based on river networks from the United States Geological Survey (USGS) Geospatial Fabric (GF) data set in which over 54 000 river segments and their contributing areas are mapped across the contiguous United States (CONUS). A brief analysis of model parameter sensitivity is also provided. The mizuRoute tool can assist model-based water resources assessments including studies of the impacts of climate change on streamflow.

Route prediction model of infectious diseases for 2018 Winter Olympics in Korea

International Nuclear Information System (INIS)

Kim, Eungyeong; Lee, Seok; Byun, Young Tae; Kim, Jae Hun; Lee, Taikjin; Lee, Hyuk-jae

2014-01-01

There are many types of respiratory infectious diseases caused by germs, virus, mycetes and parasites. Researchers recently have tried to develop mathematical models to predict the epidemic of infectious diseases. However, with the development of ground transportation system in modern society, the spread of infectious diseases became faster and more complicated in terms of the speed and the pathways. The route of infectious diseases during Vancouver Olympics was predicted based on the Susceptible-Infectious-Recovered (SIR) model. In this model only the air traffic as an essential factor for the intercity migration of infectious diseases was involved. Here, we propose a multi-city transmission model to predict the infection route during 2018 Winter Olympics in Korea based on the pre-existing SIR model. Various types of transportation system such as a train, a car, a bus, and an airplane for the interpersonal contact in both inter- and intra-city are considered. Simulation is performed with assumptions and scenarios based on realistic factors including demographic, transportation and diseases data in Korea. Finally, we analyze an economic profit and loss caused by the variation of the number of tourists during the Olympics

Route prediction model of infectious diseases for 2018 Winter Olympics in Korea

Science.gov (United States)

Kim, Eungyeong; Lee, Seok; Byun, Young Tae; Kim, Jae Hun; Lee, Hyuk-jae; Lee, Taikjin

2014-03-01

There are many types of respiratory infectious diseases caused by germs, virus, mycetes and parasites. Researchers recently have tried to develop mathematical models to predict the epidemic of infectious diseases. However, with the development of ground transportation system in modern society, the spread of infectious diseases became faster and more complicated in terms of the speed and the pathways. The route of infectious diseases during Vancouver Olympics was predicted based on the Susceptible-Infectious-Recovered (SIR) model. In this model only the air traffic as an essential factor for the intercity migration of infectious diseases was involved. Here, we propose a multi-city transmission model to predict the infection route during 2018 Winter Olympics in Korea based on the pre-existing SIR model. Various types of transportation system such as a train, a car, a bus, and an airplane for the interpersonal contact in both inter- and intra-city are considered. Simulation is performed with assumptions and scenarios based on realistic factors including demographic, transportation and diseases data in Korea. Finally, we analyze an economic profit and loss caused by the variation of the number of tourists during the Olympics.

Convergent evolution of the genomes of marine mammals

Science.gov (United States)

Foote, Andrew D.; Liu, Yue; Thomas, Gregg W.C.; Vinař, Tomáš; Alföldi, Jessica; Deng, Jixin; Dugan, Shannon; van Elk, Cornelis E.; Hunter, Margaret; Joshi, Vandita; Khan, Ziad; Kovar, Christie; Lee, Sandra L.; Lindblad-Toh, Kerstin; Mancia, Annalaura; Nielsen, Rasmus; Qin, Xiang; Qu, Jiaxin; Raney, Brian J.; Vijay, Nagarjun; Wolf, Jochen B. W.; Hahn, Matthew W.; Muzny, Donna M.; Worley, Kim C.; Gilbert, M. Thomas P.; Gibbs, Richard A.

2015-01-01

Marine mammals from different mammalian orders share several phenotypic traits adapted to the aquatic environment and therefore represent a classic example of convergent evolution. To investigate convergent evolution at the genomic level, we sequenced and performed de novo assembly of the genomes of three species of marine mammals (the killer whale, walrus and manatee) from three mammalian orders that share independently evolved phenotypic adaptations to a marine existence. Our comparative genomic analyses found that convergent amino acid substitutions were widespread throughout the genome and that a subset of these substitutions were in genes evolving under positive selection and putatively associated with a marine phenotype. However, we found higher levels of convergent amino acid substitutions in a control set of terrestrial sister taxa to the marine mammals. Our results suggest that, whereas convergent molecular evolution is relatively common, adaptive molecular convergence linked to phenotypic convergence is comparatively rare.

Convergence Insufficiency

Science.gov (United States)

... is also found to be weak. If both accommodation and convergence are weak, reading glasses, sometimes with prism added, may be a great option for these patients. It is very difficult to improve accommodation with exercises. Updated 7/2017 Eye Terms & Conditions ...

Developing an eco-routing application.

Science.gov (United States)

2014-01-01

The study develops eco-routing algorithms and investigates and quantifies the system-wide impacts of implementing an eco-routing system. Two eco-routing algorithms are developed: one based on vehicle sub-populations (ECO-Subpopulation Feedback Assign...

Temporal migration patterns between natal locations of ruby-throated hummingbirds (Archilochus colubris) and their Gulf Coast stopover site.

Science.gov (United States)

Zenzal, Theodore J; Contina, Andrea J; Kelly, Jeffrey F; Moore, Frank R

2018-01-01

Autumn latitudinal migrations generally exhibit one of two different temporal migration patterns: type 1 where southern populations migrate south before northern populations, or type 2 where northern populations overtake southern populations en route . The ruby-throated hummingbird ( Archilochus colubris ) is a species with an expansive breeding range, which allows opportunities to examine variation in the timing of migration. Our objective was to determine a relationship between natal origin of ruby-throated hummingbirds and arrival at a Gulf coast stopover site; and if so, what factors, such as differences in body size across the range as well as the cost of migration, might drive such a pattern. To carry out our objectives, we captured hummingbirds at a coastal stopover site during autumn migration, at which time we collected feathers from juveniles for analysis of hydrogen stable isotopes. Using the hydrogen stable isotope gradient of precipitation across North America and published hydrogen isotope values of feathers from populations of breeding ruby-throated hummingbirds, we assigned migrants to probable natal latitudes. Our results confirm that individuals from across the range (30-50° N) stopover along the Gulf of Mexico and there is a positive relationship between arrival day and latitude, suggesting a type 1 migration pattern. We also found no relationship between fuel load (proxy for migration cost) or fat-free body mass (proxy for body size) and natal latitude. Our results, coupled with previous work on the spatial migration patterns of hummingbirds, show a type 1 chain migration pattern. While the mechanisms we tested do not seem to influence the evolution of migratory patterns, other factors such as resource availability may play a prominent role in the evolution of this migration system.

Tuberculosis, human rights and ethics considerations along the route of a highly vulnerable migrant from sub-Saharan Africa to Europe.

Science.gov (United States)

Wild, V; Jaff, D; Shah, N S; Frick, M

2017-10-01

Migrant health is a critical public health issue, and in many countries attention to this topic has focused on the link between migration and communicable diseases, including tuberculosis (TB). When creating public health policies to address the complex challenges posed by TB and migration, countries should focus these policies on evidence, ethics, and human rights. This paper traces a commonly used migration route from sub-Saharan Africa to Europe, identifying situations at each stage in which human rights and ethical values might be affected in relation to TB care. This illustration provides the basis for discussing TB and migration from the perspective of human rights, with a focus on the right to health. We then highlight three strands of discussion in the ethics and justice literature in an effort to develop more comprehensive ethics of migrant health. These strands include theories of global justice and global health ethics, the creation of 'firewalls' to separate enforcement of immigration law from protection of human rights, and the importance of non-stigmatization to health justice. The paper closes by reflecting briefly on how TB programs can better incorporate human rights and ethical principles and values into public health practice.

Internal migration, center-state grants, and economic growth in the states of India.

Science.gov (United States)

Cashin, P; Sahay, R

1996-03-01

"This paper examines the growth experience of 20 states of India during 1961-91, using cross-sectional estimation and the analytical framework of the Solow-Swan neoclassical growth model. We find evidence of absolute convergence--initially poor states grew faster than their initially rich counterparts. Also, the dispersion of real per capita state incomes widened over the period 1961-91. However, relatively more grants were transferred from the central government to the poor states than to their rich counterparts. Significant barriers to population flows also exist, as net migration from poor to rich states responded only weakly to cross-state income differentials." excerpt

Convergence theorems for Banach space valued integrable multifunctions

Directory of Open Access Journals (Sweden)

Nikolaos S. Papageorgiou

1987-01-01

Full Text Available In this work we generalize a result of Kato on the pointwise behavior of a weakly convergent sequence in the Lebesgue-Bochner spaces LXP(Ω (1≤p≤∞. Then we use that result to prove Fatou's type lemmata and dominated convergence theorems for the Aumann integral of Banach space valued measurable multifunctions. Analogous convergence results are also proved for the sets of integrable selectors of those multifunctions. In the process of proving those convergence theorems we make some useful observations concerning the Kuratowski-Mosco convergence of sets.

Weak convergence and uniform normalization in infinitary rewriting

DEFF Research Database (Denmark)

Simonsen, Jakob Grue

2010-01-01

the starkly surprising result that for any orthogonal system with finitely many rules, the system is weakly normalizing under weak convergence if{f} it is strongly normalizing under weak convergence if{f} it is weakly normalizing under strong convergence if{f} it is strongly normalizing under strong...... convergence. As further corollaries, we derive a number of new results for weakly convergent rewriting: Systems with finitely many rules enjoy unique normal forms, and acyclic orthogonal systems are confluent. Our results suggest that it may be possible to recover some of the positive results for strongly...

Arthropods and associated arthropod-borne diseases transmitted by migrating birds. The case of ticks and tick-borne pathogens.

Science.gov (United States)

Sparagano, Olivier; George, David; Giangaspero, Annunziata; Špitalská, Eva

2015-09-30

Geographic spread of parasites and pathogens poses a constant risk to animal health and welfare, particularly given that climate change is expected to potentially expand appropriate ranges for many key species. The spread of deleterious organisms via trade routes and human travelling is relatively closely controlled, though represents only one possible means of parasite/pathogen distribution. The transmission via natural parasite/pathogen movement between geographic locales, is far harder to manage. Though the extent of such movement may be limited by the relative inability of many parasites and pathogens to actively migrate, passive movement over long distances may still occur via migratory hosts. This paper reviews the potential role of migrating birds in the transfer of ectoparasites and pathogens between geographic locales, focusing primarily on ticks. Bird-tick-pathogen relationships are considered, and evidence provided of long-range parasite/pathogen transfer from one location to another during bird migration events. As shown in this paper not only many different arthropod species are carried by migrating birds but consequently these pests carry many different pathogens species which can be transmitted to the migrating birds or to other animal species when those arthropods are dropping during these migrations. Data available from the literature are provided highlighting the need to understand better dissemination paths and disease epidemiology. Copyright © 2015 Elsevier B.V. All rights reserved.

Electricity and gas : market and price convergence : fundamentals of restructuring and convergence

Energy Technology Data Exchange (ETDEWEB)

Heintz, H.; Spragins, R.

2000-07-01

One of the results of the transition from regulation to competition in the Canadian and American natural gas and electricity industries is convergence of the two industries. Convergence is occurring in the areas of corporate structuring activities (mergers and acquisitions), natural gas and electricity prices, products and services, and on a geographic basis. This study examines the restructuring and convergence from the perspective of industry stakeholders, consumers, competitors and regulators. The trend to deregulate to establish competitive markets has been driven by the assumption that lower prices and more choices will result. Deregulation has been made easier by technological developments and innovations in the area of conventional generation, distributed generation, information management and analysis, as well as mass communication channels such as the Internet. These changes have made it possible to measure and monitor energy use in real-time. Technological changes will continue to influence the energy industry. The use of different restructuring rules and regulations in jurisdictions that are implementing change may be one of the primary factors that could limit the extent of convergence. Successful competition by energy service providers in converged retail energy markets will depend on several factors, the first of which is the ability to control the customer interface through retail cycle services such as metering and billing. The second is the successful branding of corporate identities, products and services. These will ensure customer loyalty and facilitate the marketing of new products. Another factor would be the effective management of information regarding natural gas and electricity consumption patterns and the establishment of low cost operations through the use of conventional generation technologies. The final factor for successful competition is the effective use of low cost communication technologies such as the Internet. The transition

Electricity and gas : market and price convergence : fundamentals of restructuring and convergence

International Nuclear Information System (INIS)

Heintz, H.; Spragins, R.

2000-01-01

One of the results of the transition from regulation to competition in the Canadian and American natural gas and electricity industries is convergence of the two industries. Convergence is occurring in the areas of corporate structuring activities (mergers and acquisitions), natural gas and electricity prices, products and services, and on a geographic basis. This study examines the restructuring and convergence from the perspective of industry stakeholders, consumers, competitors and regulators. The trend to deregulate to establish competitive markets has been driven by the assumption that lower prices and more choices will result. Deregulation has been made easier by technological developments and innovations in the area of conventional generation, distributed generation, information management and analysis, as well as mass communication channels such as the Internet. These changes have made it possible to measure and monitor energy use in real-time. Technological changes will continue to influence the energy industry. The use of different restructuring rules and regulations in jurisdictions that are implementing change may be one of the primary factors that could limit the extent of convergence. Successful competition by energy service providers in converged retail energy markets will depend on several factors, the first of which is the ability to control the customer interface through retail cycle services such as metering and billing. The second is the successful branding of corporate identities, products and services. These will ensure customer loyalty and facilitate the marketing of new products. Another factor would be the effective management of information regarding natural gas and electricity consumption patterns and the establishment of low cost operations through the use of conventional generation technologies. The final factor for successful competition is the effective use of low cost communication technologies such as the Internet. The transition

Migrations and swimming capabilities of endangered pallid sturgeon (Scaphirhynchus albus) to guide passage designs in the fragmented Yellowstone River

Science.gov (United States)

Braaten, P. J.; Elliott, Caroline M.; Rhoten, Jason C.; Fuller, D. B.; McElroy, Brandon J.

2015-01-01

Fragmentation of the Yellowstone River is hypothesized to preclude recruitment of endangered Scaphirhynchus albus (pallid sturgeon) by impeding upstream spawning migrations and access to upstream spawning areas, thereby limiting the length of free-flowing river required for survival of early life stages. Building on this hypothesis, the reach of the Yellowstone River affected by Intake Diversion Dam (IDD) is targeted for modification. Structures including a rock ramp and by-pass channel have been proposed as restoration alternatives to facilitate passage. Limited information on migrations and swimming capabilities of pallid sturgeon is available to guide engineering design specifications for the proposed structures. Migration behavior, pathways (channel routes used during migrations), and swimming capabilities of free-ranging wild adult pallid sturgeon were examined using radiotelemetry, and complemented with hydraulic data obtained along the migration pathways. Migrations of 12–26% of the telemetered pallid sturgeon population persisted to IDD, but upstream passage over the dam was not detected. Observed migration pathways occurred primarily through main channel habitats; however, migrations through side channels up to 3.9 km in length were documented. The majority of pallid sturgeon used depths of 2.2–3.4 m and mean water velocities of 0.89–1.83 m/s while migrating. Results provide inferences on depths, velocities, and habitat heterogeneity of reaches successfully negotiated by pallid sturgeon that may be used to guide designs for structures facilitating passage at IDD. Passage will provide connectivity to potential upstream spawning areas on the Yellowstone River, thereby increasing the likelihood of recruitment for this endangered species.

Migration of rice planthoppers and their vectored re-emerging and novel rice viruses in East Asia

Directory of Open Access Journals (Sweden)

Akira eOtuka

2013-10-01

Full Text Available This review examines recent studies of the migration of three rice planthoppers, Laodelphax striatellus, Sogatella furcifera, and Nilaparvata lugens, in East Asia. Laodelphax striatellus has recently broken out in Jiangsu province, eastern China. The population density in the province started to increase in the early 2000s and peaked in 2004. In 2005, Rice stripe virus (RSV viruliferous rate of L. striatellus peaked at 31.3%. Since then, rice stripe disease spread severely across the whole province. Due to the migration of the RSV vectors, the rice stripe disease spread to neighboring countries Japan and Korea. An overseas migration of L. striatellus that occurred in 2008 was analyzed, when a slow-moving cold vortex, a type of low pressure system, reached western Japan from Jiangsu, carrying the insects into Japan. Subsequently the rice stripe diseases struck these areas in Japan severely. In Korea, similar situations occurred in 2009, 2011, and 2012. Their migration sources were also estimated to be in Jiangsu by backward trajectory analysis. Rice black-streaked dwarf virus, whose vector is L. striatellus, has recently re-emerged in eastern China, and the evidence for overseas migrations of the virus, just like the RSV’s migrations, has been given. A method of predicting the overseas migration of L. striatellus has been developed by Japanese, Chinese, and Korean institutes. An evaluation of the prediction showed that this method properly predicted migration events that occurred in East Asia from 2008 to 2011. Southern rice black-streaked dwarf virus (SRBSDV was first found in Guangdong province. Its vector is S. furcifera. An outbreak of SRBSDV occurred in southern China in 2009 and spread to Vietnam the same year. This disease and virus were also found in Japan in 2010. The epidemic triggered many migration studies to investigate concrete spring-summer migration routes in China, and the addition of migration sources for early arrivals in

Robustness of airline route networks

Science.gov (United States)

Lordan, Oriol; Sallan, Jose M.; Escorihuela, Nuria; Gonzalez-Prieto, David

2016-03-01

Airlines shape their route network by defining their routes through supply and demand considerations, paying little attention to network performance indicators, such as network robustness. However, the collapse of an airline network can produce high financial costs for the airline and all its geographical area of influence. The aim of this study is to analyze the topology and robustness of the network route of airlines following Low Cost Carriers (LCCs) and Full Service Carriers (FSCs) business models. Results show that FSC hubs are more central than LCC bases in their route network. As a result, LCC route networks are more robust than FSC networks.

Migration challenges among Zimbabwean refugees before, during and post arrival in South Africa.

Science.gov (United States)

Idemudia, Erhabor Sunday; Williams, John K; Wyatt, Gail E

2013-01-01

Zimbabweans are immigrating to South Africa with a commonly cited reason being economic opportunities. Prospects of finding employment may be a significant reason to leave behind family, friends, and community, sources that buffer and offer social support against life's challenges. Currently, there is a dearth of research examining the motivators for Zimbabweans immigrating and the experiences encountered along the way and after arrival in South Africa. Such research is essential as large numbers of Zimbabweans may be at risk for emotional and physical trauma during this process. Two gender specific focus group discussions, each lasting 90-minutes and consisting of homeless Zimbabwean refugees, were conducted in the Limpopo Province of South Africa. A semi-structured interview assessed for experiences in and reasons for leaving Zimbabwe, as well as experiences en-route and within South Africa. Discussions were audio-recorded, transcribed, and analyzed using consensual qualitative research and a constant comparison qualitative method. Three temporal themes were identified and included challenges and trauma experienced in Zimbabwe (pre-migration), during the immigration journey (mid-migration), and upon arrival in South Africa (post-migration). While there were some experiential differences, Zimbabwean men and women shared numerous traumatic commonalities. In addition to the themes, three subthemes contributing to reasons for leaving Zimbabwe, two subthemes of negative and traumatic experiences incurred mid-migration, and two post-migration subthemes of challenges were identified. Despite the difficulties encountered in their homeland, newly arrived Zimbabweans in South Africa may be exchanging old struggles for a new array of foreign and traumatic challenges. Reasons to immigrate and the psychological and physical toll of migration exacted at the individual and community levels are discussed. Recommendations advocating for culturally congruent mental health research

The potential of fruit trees to enhance converted habitats for migrating birds in southern Mexico

Science.gov (United States)

Foster, M.S.

2007-01-01

Migration routes used by Nearctic migrant birds can cover great distances; they also differ among species, within species, and between years and seasons. As a result, migration routes for an entire migratory avifauna can encompass broad geographic areas, making it impossible to protect continuous stretches of habitat sufficient to connect the wintering and breeding grounds for most species. Consequently, ways to enhance habitats converted for human use (i.e. for pasture, crop cultivation, human settlement) as stopover sites for migrants are especially important. Shelterbelts around pastures and fields, if planted with species targeted to support migrant (and resident) bird species that naturally occupy mature forest habitats and that are at least partially frugivorous, could be a powerful enhancement tool for such species, if the birds will enter the converted areas to feed. I tested this approach for Nearctic migrant birds during the spring migration through an area in Chiapas, Mexico. Mature forest tree species whose fruits are eaten by birds were surveyed. Based on life form, crop size and fruit characteristics, I selected three tree species for study: Cymbopetalum mayanum (Annonaceae), Bursera simaruba (Burseraceae) and Trophis racemosa (Moraceae). I compared the use of fruits of these species by migrants and residents in forest with their use of the fruits of isolated individuals of the same species in pasture and cropland. All three plant species were useful for enhancing converted habitats for forest-occupying spring migrants, although species differed in the degree to which they entered disturbed areas to feed on the fruits. These tree species could probably enhance habitats for migrants at sites throughout the natural geographic ranges of the plants; in other geographic areas for other target bird groups, other tree species might be more appropriate.

Quadratically convergent MCSCF scheme using Fock operators

International Nuclear Information System (INIS)

Das, G.

1981-01-01

A quadratically convergent formulation of the MCSCF method using Fock operators is presented. Among its advantages the present formulation is quadratically convergent unlike the earlier ones based on Fock operators. In contrast to other quadratically convergent schemes as well as the one based on generalized Brillouin's theorem, this method leads easily to a hybrid scheme where the weakly coupled orbitals (such as the core) are handled purely by Fock equations, while the rest of the orbitals are treated by a quadratically convergent approach with a truncated virtual space obtained by the use of the corresponding Fock equations

Factors affecting route selection and survival of steelhead kelts at Snake River dams in 2012 and 2013

Energy Technology Data Exchange (ETDEWEB)

Harnish, Ryan A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Colotelo, Alison H. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Li, Xinya [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fu, Tao [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ham, Kenneth D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deng, Zhiqun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Green, Ethan D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-03-31

In 2012 and 2013, Pacific Northwest National Laboratory (PNNL) conducted a study that summarized the passage route proportions and route-specific survival rates of steelhead kelts that passed through Federal Columbia River Power System (FCRPS) dams. To accomplish this, a total of 811 steelhead kelts were tagged with Juvenile Salmon Acoustic Telemetry System (JSATS) transmitters. Acoustic receivers, both autonomous and cabled, were deployed throughout the FCRPS to monitor the downstream movements of tagged kelts. Kelts were also tagged with passive integrated transponder tags to monitor passage through juvenile bypass systems (JBS) and detect returning fish. The current study evaluated data collected in 2012 and 2013 to identify environmental, temporal, operational, individual, and behavioral variables that were related to forebay residence time, route of passage, and survival of steelhead kelts at FCRPS dams on the Snake River. Multiple approaches, including 3-D tracking, bivariate and multivariable regression modeling, and decision tree analyses were used to identify the environmental, temporal, operational, individual, and behavioral variables that had the greatest effect on forebay residence time, route of passage, and route-specific and overall dam passage survival probabilities for tagged kelts at Lower Granite (LGR), Little Goose (LGS), and Lower Monumental (LMN) dams. In general, kelt behavior and discharge appeared to work independently to affect forebay residence times. Kelt behavior, primarily approach location, migration depth, and “searching” activities in the forebay, was found to have the greatest influence on their route of passage. The condition of kelts was the single most important factor affecting their survival. The information gathered in this study may be used by dam operators and fisheries managers to identify potential management actions to improve in-river survival of kelts or collection methods for kelt reconditioning programs to aid

A floating bridge disrupts seaward migration and increases mortality of steelhead smolts in Hood Canal, Washington state.

Directory of Open Access Journals (Sweden)

Megan Moore

Full Text Available Habitat modifications resulting from human transportation and power-generation infrastructure (e.g., roads, dams, bridges can impede movement and alter natural migration patterns of aquatic animal populations, which may negatively affect survival and population viability. Full or partial barriers are especially problematic for migratory species whose life histories hinge on habitat connectivity.The Hood Canal Bridge, a floating structure spanning the northern outlet of Hood Canal in Puget Sound, Washington, extends 3.6 meters underwater and forms a partial barrier for steelhead migrating from Hood Canal to the Pacific Ocean. We used acoustic telemetry to monitor migration behavior and mortality of steelhead smolts passing four receiver arrays and several single receivers within the Hood Canal, Puget Sound, and Strait of Juan de Fuca. Twenty-seven mortality events were detected within the vicinity of the Hood Canal Bridge, while only one mortality was recorded on the other 325 receivers deployed throughout the study area. Migrating steelhead smolts were detected at the Hood Canal Bridge array with greater frequency, on more receivers, and for longer durations than smolts migrating past three comparably configured arrays. Longer migration times and paths are likely to result in a higher density of smolts near the bridge in relation to other sites along the migration route, possibly inducing an aggregative predator response to steelhead smolts.This study provides strong evidence of substantial migration interference and increased mortality risk associated with the Hood Canal Bridge, and may partially explain low early marine survival rates observed in Hood Canal steelhead populations. Understanding where habitat modifications indirectly increase predation pressures on threatened populations helps inform potential approaches to mitigation.

A floating bridge disrupts seaward migration and increases mortality of steelhead smolts in Hood Canal, Washington state.

Science.gov (United States)

Moore, Megan; Berejikian, Barry A; Tezak, Eugene P

2013-01-01

Habitat modifications resulting from human transportation and power-generation infrastructure (e.g., roads, dams, bridges) can impede movement and alter natural migration patterns of aquatic animal populations, which may negatively affect survival and population viability. Full or partial barriers are especially problematic for migratory species whose life histories hinge on habitat connectivity. The Hood Canal Bridge, a floating structure spanning the northern outlet of Hood Canal in Puget Sound, Washington, extends 3.6 meters underwater and forms a partial barrier for steelhead migrating from Hood Canal to the Pacific Ocean. We used acoustic telemetry to monitor migration behavior and mortality of steelhead smolts passing four receiver arrays and several single receivers within the Hood Canal, Puget Sound, and Strait of Juan de Fuca. Twenty-seven mortality events were detected within the vicinity of the Hood Canal Bridge, while only one mortality was recorded on the other 325 receivers deployed throughout the study area. Migrating steelhead smolts were detected at the Hood Canal Bridge array with greater frequency, on more receivers, and for longer durations than smolts migrating past three comparably configured arrays. Longer migration times and paths are likely to result in a higher density of smolts near the bridge in relation to other sites along the migration route, possibly inducing an aggregative predator response to steelhead smolts. This study provides strong evidence of substantial migration interference and increased mortality risk associated with the Hood Canal Bridge, and may partially explain low early marine survival rates observed in Hood Canal steelhead populations. Understanding where habitat modifications indirectly increase predation pressures on threatened populations helps inform potential approaches to mitigation.

Exposure to Traumatic Experiences Among Asylum Seekers from Eritrea and Sudan During Migration to Israel.

Science.gov (United States)

Nakash, Ora; Langer, Benjamin; Nagar, Maayan; Shoham, Shahar; Lurie, Ido; Davidovitch, Nadav

2015-08-01

Little is known about the experiences of displaced individuals en route to destination countries. We investigated the reported prevalence of exposure to traumatic experiences during migration among a consecutive sample of adult asylum seekers (n = 895 Eritrean, n = 149 Sudanese) who sought health services in the Physicians for Human Rights Open-Clinic in Israel. Percentage of Eritrean and Sudanese men and women who reported witnessing violence (Eritrea: men: 41.3 %, women: 29.3 %; Sudan: men: 16.8 %, women: 22.2 %) and/or being a victim of violence (Eritrea: men: 56.0 %, Women: 34.9 %; Sudan: men: 51.9 % women: 44.4 %) during migration varied by gender and country of origin. Findings highlight the need for a well-coordinated international cooperation to document and prevent these transgressions.

a globally convergent hyperpl onvergent hyperplane

African Journals Online (AJOL)

userpc

Bayero Journal of Pure and App. ISSN 2006 – 6996 ... Globally Convergent Hyper plane-BFGS method for solving nonline. The attractive ... Numerical performance on some b rates there liability ..... convergence of a class of quasi methods on ...

An overview of smart grid routing algorithms

Science.gov (United States)

Wang, Junsheng; OU, Qinghai; Shen, Haijuan

2017-08-01

This paper summarizes the typical routing algorithm in smart grid by analyzing the communication business and communication requirements of intelligent grid. Mainly from the two kinds of routing algorithm is analyzed, namely clustering routing algorithm and routing algorithm, analyzed the advantages and disadvantages of two kinds of typical routing algorithm in routing algorithm and applicability.

Family migration and employment: the importance of migration history and gender.

Science.gov (United States)

Bailey, A J; Cooke, T J

1998-01-01

"This article uses event history data to specify a model of employment returns to initial migration, onward migration, and return migration among newly married persons in the U.S. Husbands are more likely to be full-time employed than wives, and being a parent reduces the employment odds among married women. Employment returns to repeated migration differ by gender, with more husbands full-time employed after onward migration and more wives full-time employed after return migration events. We interpret these empirical findings in the context of family migration theory, segmented labor market theory, and gender-based responsibilities." Data are from the National Longitudinal Survey of Youth from 1979 to 1991. excerpt

A preference for migration

OpenAIRE

Stark, Oded

2007-01-01

At least to some extent migration behavior is the outcome of a preference for migration. The pattern of migration as an outcome of a preference for migration depends on two key factors: imitation technology and migration feasibility. We show that these factors jointly determine the outcome of a preference for migration and we provide examples that illustrate how the prevalence and transmission of a migration-forming preference yield distinct migration patterns. In particular, the imitation of...

Goliath catfish spawning in the far western Amazon confirmed by the distribution of mature adults, drifting larvae and migrating juveniles.

Science.gov (United States)

Barthem, Ronaldo B; Goulding, Michael; Leite, Rosseval G; Cañas, Carlos; Forsberg, Bruce; Venticinque, Eduardo; Petry, Paulo; Ribeiro, Mauro L de B; Chuctaya, Junior; Mercado, Armando

2017-02-06

We mapped the inferred long-distance migrations of four species of Amazonian goliath catfishes (Brachyplatystoma rousseauxii, B. platynemum, B. juruense and B. vaillantii) based on the presence of individuals with mature gonads and conducted statistical analysis of the expected long-distance downstream migrations of their larvae and juveniles. By linking the distribution of larval, juvenile and mature adult size classes across the Amazon, the results showed: (i) that the main spawning regions of these goliath catfish species are in the western Amazon; (ii) at least three species-B. rousseauxii, B. platynemum, and B. juruense-spawn partially or mainly as far upstream as the Andes; (iii) the main spawning area of B. rousseauxii is in or near the Andes; and (iv) the life history migration distances of B. rousseauxii are the longest strictly freshwater fish migrations in the world. These results provide an empirical baseline for tagging experiments, life histories extrapolated from otolith microchemistry interpretations and other methods to establish goliath catfish migratory routes, their seasonal timing and possible return (homing) to western headwater tributaries where they were born.

The Mackey convergence condition for spaces with webs

Directory of Open Access Journals (Sweden)

Thomas E. Gilsdorf

1988-01-01

Full Text Available If each sequence converging to 0 in a locally convex space is also Mackey convergent to 0, that space is said to satisfy the Mackey convergence condition. The problem of characterizing those locally convex spaces with this property is still open. In this paper, spaces with compatible webs are used to construct both a necessary and a sufficient condition for a locally convex space to satisfy the Mackey convergence condition.

On the Fuzzy Convergence

Directory of Open Access Journals (Sweden)

Abdul Hameed Q. A. Al-Tai

2011-01-01

Full Text Available The aim of this paper is to introduce and study the fuzzy neighborhood, the limit fuzzy number, the convergent fuzzy sequence, the bounded fuzzy sequence, and the Cauchy fuzzy sequence on the base which is adopted by Abdul Hameed (every real number r is replaced by a fuzzy number r¯ (either triangular fuzzy number or singleton fuzzy set (fuzzy point. And then, we will consider that some results respect effect of the upper sequence on the convergent fuzzy sequence, the bounded fuzzy sequence, and the Cauchy fuzzy sequence.

Southern states' routing agency report

International Nuclear Information System (INIS)

1989-02-01

The Southern states' routing agency report is a compendium of 16-southern states' routing programs relative to the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source ad scope of the agencies' rulemaking authority. Additionally, the state agency and contact designated by the state's governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed

Southern States' Routing Agency Report

International Nuclear Information System (INIS)

1990-03-01

The Southern States' Routing Agency Report is a compendium of 16-southern states' routing program for the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source and scope of the agencies' rulemaking authority. Additionally, the state agency and contact designated by the state's governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed

On statistical acceleration convergence of double sequences

Directory of Open Access Journals (Sweden)

Bipan Hazarika

2017-04-01

Full Text Available In this article the notion of statistical acceleration convergence of double sequences in Pringsheim's sense has been introduced. We prove the decompostion theorems for  statistical acceleration convergence of double sequences and some theorems related to that concept have been established using the four dimensional matrix transformations. We provided some examples, where the results of acceleration convergence fails to hold for the statistical cases.

Convergence of carbon dioxide emissions in different sectors in China

International Nuclear Information System (INIS)

Wang, Juan; Zhang, Kezhong

2014-01-01

In this paper, we analyze differences in per capita carbon dioxide emissions from 1996 to 2010 in six sectors across 28 provinces in China and examine the σ-convergence, stochastic convergence and β-convergence of these emissions. We also investigate the factors that impact the convergence of per capita carbon dioxide emissions in each sector. The results show that per capita carbon dioxide emissions in all sectors converged across provinces from 1996 to 2010. Factors that impact the convergence of per capita carbon dioxide emissions in each sector vary: GDP (gross domestic product) per capita, industrialization process and population density impact convergence in the Industry sector, while GDP per capita and population density impact convergence in the Transportation, Storage, Postal, and Telecommunications Services sector. Aside from GDP per capita and population density, trade openness also impacts convergence in the Wholesale, Retail, Trade, and Catering Service sector. Population density is the only factor that impacts convergence in the Residential Consumption sector. - Highlights: • Analyze differences in CO 2 emissions in six sectors among 28 provinces in China. • Examine the convergence of CO 2 emissions in six sectors. • Investigate factors impact on convergence of CO 2 emissions in each sector. • Factors impact on convergence of per capita CO 2 emissions in each sector vary

Load Balancing Routing with Bounded Stretch

Directory of Open Access Journals (Sweden)

Chen Siyuan

2010-01-01

Full Text Available Routing in wireless networks has been heavily studied in the last decade. Many routing protocols are based on classic shortest path algorithms. However, shortest path-based routing protocols suffer from uneven load distribution in the network, such as crowed center effect where the center nodes have more load than the nodes in the periphery. Aiming to balance the load, we propose a novel routing method, called Circular Sailing Routing (CSR, which can distribute the traffic more evenly in the network. The proposed method first maps the network onto a sphere via a simple stereographic projection, and then the route decision is made by a newly defined "circular distance" on the sphere instead of the Euclidean distance in the plane. We theoretically prove that for a network, the distance traveled by the packets using CSR is no more than a small constant factor of the minimum (the distance of the shortest path. We also extend CSR to a localized version, Localized CSR, by modifying greedy routing without any additional communication overhead. In addition, we investigate how to design CSR routing for 3D networks. For all proposed methods, we conduct extensive simulations to study their performances and compare them with global shortest path routing or greedy routing in 2D and 3D wireless networks.

Quantifying convergence in the sciences

Directory of Open Access Journals (Sweden)

Sara Lumbreras

2016-02-01

Full Text Available Traditional epistemological models classify knowledge into separate disciplines with different objects of study and specific techniques, with some frameworks even proposing hierarchies (such as Comte’s. According to thinkers such as John Holland or Teilhard de Chardin, the advancement of science involves the convergence of disciplines. This proposed convergence can be studied in a number of ways, such as how works impact research outside a specific area (citation networks or how authors collaborate with other researchers in different fields (collaboration networks. While these studies are delivering significant new insights, they cannot easily show the convergence of different topics within a body of knowledge. This paper attempts to address this question in a quantitative manner, searching for evidence that supports the idea of convergence in the content of the sciences themselves (that is, whether the sciences are dealing with increasingly the same topics. We use Latent Dirichlet Analysis (LDA, a technique that is able to analyze texts and estimate the relative contributions of the topics that were used to generate them. We apply this tool to the corpus of the Santa Fe Institute (SFI working papers, which spans research on Complexity Science from 1989 to 2015. We then analyze the relatedness of the different research areas, the rise and demise of these sub-disciplines over time and, more broadly, the convergence of the research body as a whole. Combining the topic structure obtained from the collected publication history of the SFI community with techniques to infer hierarchy and clustering, we reconstruct a picture of a dynamic community which experiences trends, periodically recurring topics, and shifts in the closeness of scholarship over time. We find that there is support for convergence, and that the application of quantitative methods such as LDA to the study of knowledge can provide valuable insights that can help

Vehicle routing problem with time windows using natural inspired algorithms

Science.gov (United States)

Pratiwi, A. B.; Pratama, A.; Sa’diyah, I.; Suprajitno, H.

2018-03-01

Process of distribution of goods needs a strategy to make the total cost spent for operational activities minimized. But there are several constrains have to be satisfied which are the capacity of the vehicles and the service time of the customers. This Vehicle Routing Problem with Time Windows (VRPTW) gives complex constrains problem. This paper proposes natural inspired algorithms for dealing with constrains of VRPTW which involves Bat Algorithm and Cat Swarm Optimization. Bat Algorithm is being hybrid with Simulated Annealing, the worst solution of Bat Algorithm is replaced by the solution from Simulated Annealing. Algorithm which is based on behavior of cats, Cat Swarm Optimization, is improved using Crow Search Algorithm to make simplier and faster convergence. From the computational result, these algorithms give good performances in finding the minimized total distance. Higher number of population causes better computational performance. The improved Cat Swarm Optimization with Crow Search gives better performance than the hybridization of Bat Algorithm and Simulated Annealing in dealing with big data.

Guidelines for selecting preferred highway routes for highway-route-controlled quantity shipments of radioactive materials

International Nuclear Information System (INIS)

1989-01-01

The document presents guidelines for use by State officials in selecting preferred routes for highway route controlled quantity shipments of radioactive materials. A methodology for analyzing and comparing safety factors of alternative routes is described. Technical information on the impacts of radioactive material transportation needed to apply the methodology is also presented. Application of the methodology will identify the route (or set of routes) that minimizes the radiological impacts from shipments of these radioactive materials within a given State. Emphasis in the document is on practical application of the methodology. Some details of the derivation of the methods and data are presented in the appendices. All references in the body of the report can be found listed in the Bibliography (Appendix F)

Beyond Brainstorming: Exploring Convergence in Teams

DEFF Research Database (Denmark)

Seeber, Isabella; de Vreede, Gert-Jan; Maier, Ronald

2017-01-01

Collaborative brainstorming is often followed by a convergence activity where teams extract the most promising ideas on a useful level of detail from the brainstorming results. Contrary to the wealth of research on electronic brainstorming, there is a dearth of research on convergence. We used...

Convergence analysis of canonical genetic algorithms.

Science.gov (United States)

Rudolph, G

1994-01-01

This paper analyzes the convergence properties of the canonical genetic algorithm (CGA) with mutation, crossover and proportional reproduction applied to static optimization problems. It is proved by means of homogeneous finite Markov chain analysis that a CGA will never converge to the global optimum regardless of the initialization, crossover, operator and objective function. But variants of CGA's that always maintain the best solution in the population, either before or after selection, are shown to converge to the global optimum due to the irreducibility property of the underlying original nonconvergent CGA. These results are discussed with respect to the schema theorem.

convergent methods for calculating thermodynamic Green functions

OpenAIRE

Bowen, S. P.; Williams, C. D.; Mancini, J. D.

1984-01-01

A convergent method of approximating thermodynamic Green functions is outlined briefly. The method constructs a sequence of approximants which converges independently of the strength of the Hamiltonian's coupling constants. Two new concepts associated with the approximants are introduced: the resolving power of the approximation, and conditional creation (annihilation) operators. These ideas are illustrated on an exactly soluble model and a numerical example. A convergent expression for the s...

Log-binomial models: exploring failed convergence.

Science.gov (United States)

Williamson, Tyler; Eliasziw, Misha; Fick, Gordon Hilton

2013-12-13

Relative risk is a summary metric that is commonly used in epidemiological investigations. Increasingly, epidemiologists are using log-binomial models to study the impact of a set of predictor variables on a single binary outcome, as they naturally offer relative risks. However, standard statistical software may report failed convergence when attempting to fit log-binomial models in certain settings. The methods that have been proposed in the literature for dealing with failed convergence use approximate solutions to avoid the issue. This research looks directly at the log-likelihood function for the simplest log-binomial model where failed convergence has been observed, a model with a single linear predictor with three levels. The possible causes of failed convergence are explored and potential solutions are presented for some cases. Among the principal causes is a failure of the fitting algorithm to converge despite the log-likelihood function having a single finite maximum. Despite these limitations, log-binomial models are a viable option for epidemiologists wishing to describe the relationship between a set of predictors and a binary outcome where relative risk is the desired summary measure. Epidemiologists are encouraged to continue to use log-binomial models and advocate for improvements to the fitting algorithms to promote the widespread use of log-binomial models.

A class of convergent neural network dynamics

Science.gov (United States)

Fiedler, Bernold; Gedeon, Tomáš

1998-01-01

We consider a class of systems of differential equations in Rn which exhibits convergent dynamics. We find a Lyapunov function and show that every bounded trajectory converges to the set of equilibria. Our result generalizes the results of Cohen and Grossberg (1983) for convergent neural networks. It replaces the symmetry assumption on the matrix of weights by the assumption on the structure of the connections in the neural network. We prove the convergence result also for a large class of Lotka-Volterra systems. These are naturally defined on the closed positive orthant. We show that there are no heteroclinic cycles on the boundary of the positive orthant for the systems in this class.

Convergence of knowledge, technology and society beyond convergence of nano-bio-info-cognitive technologies

CERN Document Server

Bainbridge, William; Tonn, Bruce; Whitesides, George

2013-01-01

Convergence of knowledge and technology for the benefit of society (CKTS) is the core opportunity for progress in the 21st century, based on five principles: (1) the interdependence of all components of nature and society, (2) enhancement of creativity and innovation through evolutionary processes of convergence that combine existing principles, and divergence that generates new ones, (3) decision analysis for research and development based on system-logic deduction, (4) higher-level cross-domain languages to generate new solutions and support transfer of new knowledge, and (5) vision-inspired basic research embodied in grand challenges. Solutions are outlined for key societal challenges, including creating new industries and jobs, improving lifelong wellness and human potential, achieving personalized and integrated healthcare and education, and securing a sustainable quality of life for all. This report provides a ten-year “NBIC2” vision within a longer-term framework for converging technology and human...

Full Waveform Inversion Using Oriented Time Migration Method

KAUST Repository

Zhang, Zhendong

2016-04-12

Full waveform inversion (FWI) for reflection events is limited by its linearized update requirements given by a process equivalent to migration. Unless the background velocity model is reasonably accurate the resulting gradient can have an inaccurate update direction leading the inversion to converge into what we refer to as local minima of the objective function. In this thesis, I first look into the subject of full model wavenumber to analysis the root of local minima and suggest the possible ways to avoid this problem. And then I analysis the possibility of recovering the corresponding wavenumber components through the existing inversion and migration algorithms. Migration can be taken as a generalized inversion method which mainly retrieves the high wavenumber part of the model. Conventional impedance inversion method gives a mapping relationship between the migration image (high wavenumber) and model parameters (full wavenumber) and thus provides a possible cascade inversion strategy to retrieve the full wavenumber components from seismic data. In the proposed approach, consider a mild lateral variation in the model, I find an analytical Frechet derivation corresponding to the new objective function. In the proposed approach, the gradient is given by the oriented time-domain imaging method. This is independent of the background velocity. Specifically, I apply the oriented time-domain imaging (which depends on the reflection slope instead of a background velocity) on the data residual to obtain the geometrical features of the velocity perturbation. Assuming that density is constant, the conventional 1D impedance inversion method is also applicable for 2D or 3D velocity inversion within the process of FWI. This method is not only capable of inverting for velocity, but it is also capable of retrieving anisotropic parameters relying on linearized representations of the reflection response. To eliminate the cross-talk artifacts between different parameters, I

Explaining convergence of oecd welfare states

DEFF Research Database (Denmark)

Schmitt, C.; Starke, Peter

2011-01-01

of conditional convergence helps to both better describe and explain the phenomenon. By applying error correction models, we examine conditional convergence of various types of social expenditure in 21 OECD countries between 1980 and 2005. Our empirical findings go beyond the existing literature in two respects...

Japanese migration in contemporary Japan: economic segmentation and interprefectural migration.

Science.gov (United States)

Fukurai, H

1991-01-01

This paper examines the economic segmentation model in explaining 1985-86 Japanese interregional migration. The analysis takes advantage of statistical graphic techniques to illustrate the following substantive issues of interregional migration: (1) to examine whether economic segmentation significantly influences Japanese regional migration and (2) to explain socioeconomic characteristics of prefectures for both in- and out-migration. Analytic techniques include a latent structural equation (LISREL) methodology and statistical residual mapping. The residual dispersion patterns, for instance, suggest the extent to which socioeconomic and geopolitical variables explain migration differences by showing unique clusters of unexplained residuals. The analysis further points out that extraneous factors such as high residential land values, significant commuting populations, and regional-specific cultures and traditions need to be incorporated in the economic segmentation model in order to assess the extent of the model's reliability in explaining the pattern of interprefectural migration.

Strategies for Selecting Routes through Real-World Environments: Relative Topography, Initial Route Straightness, and Cardinal Direction.

Directory of Open Access Journals (Sweden)

Tad T Brunyé

Full Text Available Previous research has demonstrated that route planners use several reliable strategies for selecting between alternate routes. Strategies include selecting straight rather than winding routes leaving an origin, selecting generally south- rather than north-going routes, and selecting routes that avoid traversal of complex topography. The contribution of this paper is characterizing the relative influence and potential interactions of these strategies. We also examine whether individual differences would predict any strategy reliance. Results showed evidence for independent and additive influences of all three strategies, with a strong influence of topography and initial segment straightness, and relatively weak influence of cardinal direction. Additively, routes were also disproportionately selected when they traversed relatively flat regions, had relatively straight initial segments, and went generally south rather than north. Two individual differences, extraversion and sense of direction, predicted the extent of some effects. Under real-world conditions navigators indeed consider a route's initial straightness, cardinal direction, and topography, but these cues differ in relative influence and vary in their application across individuals.

Impacts of an underwater high voltage DC power cable on fish migration movements in the San Francisco Bay.

Science.gov (United States)

Wyman, M. T.; Kavet, R.; Klimley, A. P.

2016-02-01

There is an increasingly strong interest on a global scale in offshore renewable energy production and transportation. However, there is concern that the electromagnetic fields (EMF) produced by these underwater cables may alter the behavior and physiology of marine species. Despite this concern, few studies have investigated these effects in free-living species. In 2009, a 85 km long high-voltage DC (HVDC) power cable was placed within the San Francisco Bay, running parallel, then perpendicular to, the migration route of anadromous species moving from the inland river system to the oceans. In this study, we assess the impacts of this HVDC cable on the migration behaviors of EMF-sensitive fish, including juvenile salmonids (Chinook salmon, Oncorhynchus tshawytscha, and steelhead trout, Oncorhynchus mykiss) and adult green sturgeon, Acipenser medirostris. Acoustic telemetry techniques were used to track fish migration movements through the San Francisco Bay both before and after the cable was activated; individuals implanted with acoustic transmitters were detected on cross-channel hydrophone arrays at key locations in the system. Magnetic fields were surveyed and mapped at these locations using a transverse gradiometer, and models of the cable's magnetic field were developed that closely matched the empirically measured values. Here, we present our analyses on the relationships between migration-related behavioral metrics (e.g., percent of successful migrations, duration of migration, time spent near vs. far from cable location, etc.) and environmental parameters, such as cable activation and load level, local magnetic field levels, depth, and currents.

Routing and scheduling problems

DEFF Research Database (Denmark)

Reinhardt, Line Blander

couple of decades. To deliver competitive service and price, transportation today needs to be cost effective. A company requiring for things to be shipped will aim at having the freight shipped as cheaply as possible while often satisfying certain time constraints. For the transportation company......, the effectiveness of the network is of importance aiming at satisfying as many costumer demands as possible at a low cost. Routing represent a path between locations such as an origin and destination for the object routed. Sometimes routing has a time dimension as well as the physical paths. This may...... set cost making the cost of the individual vehicle routes inter-dependant. Depending on the problem type, the size of the problems and time available for solving, different solution methods can be applicable. In this thesis both heuristic methods and several exact methods are investigated depending...

Intelligent routing protocol for ad hoc wireless network

Science.gov (United States)

Peng, Chaorong; Chen, Chang Wen

2006-05-01

A novel routing scheme for mobile ad hoc networks (MANETs), which combines hybrid and multi-inter-routing path properties with a distributed topology discovery route mechanism using control agents is proposed in this paper. In recent years, a variety of hybrid routing protocols for Mobile Ad hoc wireless networks (MANETs) have been developed. Which is proactively maintains routing information for a local neighborhood, while reactively acquiring routes to destinations beyond the global. The hybrid protocol reduces routing discovery latency and the end-to-end delay by providing high connectivity without requiring much of the scarce network capacity. On the other side the hybrid routing protocols in MANETs likes Zone Routing Protocol still need route "re-discover" time when a route between zones link break. Sine the topology update information needs to be broadcast routing request on local zone. Due to this delay, the routing protocol may not be applicable for real-time data and multimedia communication. We utilize the advantages of a clustering organization and multi-routing path in routing protocol to achieve several goals at the same time. Firstly, IRP efficiently saves network bandwidth and reduces route reconstruction time when a routing path fails. The IRP protocol does not require global periodic routing advertisements, local control agents will automatically monitor and repair broke links. Secondly, it efficiently reduces congestion and traffic "bottlenecks" for ClusterHeads in clustering network. Thirdly, it reduces significant overheads associated with maintaining clusters. Fourthly, it improves clusters stability due to dynamic topology changing frequently. In this paper, we present the Intelligent Routing Protocol. First, we discuss the problem of routing in ad hoc networks and the motivation of IRP. We describe the hierarchical architecture of IRP. We describe the routing process and illustrate it with an example. Further, we describe the control manage

Risk assessment of alternative proliferation routes

International Nuclear Information System (INIS)

Ahmed, S.; Husseiny, A.A.

1982-01-01

Multi-Attribute Decision Theory is applied to rank II alternative routes to nuclear proliferation in order of difficulty in acquiring nuclear weapons by nonnuclear countries. The method is based on reducing the various variables affecting the decision to a single function providing a measure for the proliferation route. The results indicate that the most difficult route to obtain atomic weapons is through nuclear power reactors, specifically the liquid-metal fast breeder reactor, heavy water Canada deuterium uranium reactor, and light water reactors such as boiling water and pressurized water reactors. The easiest routes are supercritical centrifuge isotope separation, laser isotope separation, and research reactor. However, nonnuclear routes available that result in substantial damage to life and property are easier than any nuclear route

The puzzle of partial migration: Adaptive dynamics and evolutionary game theory perspectives.

Science.gov (United States)

De Leenheer, Patrick; Mohapatra, Anushaya; Ohms, Haley A; Lytle, David A; Cushing, J M

2017-01-07

We consider the phenomenon of partial migration which is exhibited by populations in which some individuals migrate between habitats during their lifetime, but others do not. First, using an adaptive dynamics approach, we show that partial migration can be explained on the basis of negative density dependence in the per capita fertilities alone, provided that this density dependence is attenuated for increasing abundances of the subtypes that make up the population. We present an exact formula for the optimal proportion of migrants which is expressed in terms of the vital rates of migrant and non-migrant subtypes only. We show that this allocation strategy is both an evolutionary stable strategy (ESS) as well as a convergence stable strategy (CSS). To establish the former, we generalize the classical notion of an ESS because it is based on invasion exponents obtained from linearization arguments, which fail to capture the stabilizing effects of the nonlinear density dependence. These results clarify precisely when the notion of a "weak ESS", as proposed in Lundberg (2013) for a related model, is a genuine ESS. Secondly, we use an evolutionary game theory approach, and confirm, once again, that partial migration can be attributed to negative density dependence alone. In this context, the result holds even when density dependence is not attenuated. In this case, the optimal allocation strategy towards migrants is the same as the ESS stemming from the analysis based on the adaptive dynamics. The key feature of the population models considered here is that they are monotone dynamical systems, which enables a rather comprehensive mathematical analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Granite ascent and emplacement during contractional deformation in convergent orogens

Science.gov (United States)

Brown, Michael; Solar, Gary S.

1998-09-01

Based on a case study in the Central Maine Belt of west-central Maine, U.S.A., it is proposed that crustal-scale shear zone systems provide an effective focussing mechanism for transfer of granite melt through the crust in convergent orogens. During contractional deformation, flow of melt in crustal materials at depths below the brittle-plastic transition is coupled with plastic deformation of these materials. The flow is driven by pressure gradients generated by buoyancy forces and tectonic stresses. Within the oblique-reverse Central Maine Belt shear zone system, stromatic migmatite and concordant to weakly discordant irregular granite sheets occur in zones of higher strain, which suggests percolative flow of melt to form the migmatite leucosomes and viscous flow of melt channelized in sheet-like bodies, possibly along fractures. Cyclic fluctuations of melt pressure may cause instantaneous changes in the effective permeability of the flow network if self-propagating melt-filled tensile and/or dilatant shear fractures are produced due to melt-enhanced embrittlement. Inhomogeneous migmatite and schlieric granite occur in zones of lower strain, which suggests migration of partially-molten material through these zones en masse by granular flow, and channelized flow of melt carrying entrained residue. Founded on the Central Maine Belt case study, we develop a model of melt extraction and ascent using the driving forces, stress conditions and crustal rheologies in convergent, especially transpressive orogens. Ascent of melt becomes inhibited with decreasing depth as the solidus is approached. For intermediate a(H 2O) muscovite-dehydration melting, the water-saturated solidus occurs between 400 and 200 MPa, near the brittle-plastic transition during high- T-low- P metamorphism, where the balance of forces favors (sub-) horizontal fracture propagation. Emplacement of melt may be accommodated by ductile flow and/or stoping of wall rock, and inflation may be accommodated

Convergence Performance of Adaptive Algorithms of L-Filters

Directory of Open Access Journals (Sweden)

Robert Hudec

2003-01-01

Full Text Available This paper deals with convergence parameters determination of adaptive algorithms, which are used in adaptive L-filters design. Firstly the stability of adaptation process, convergence rate or adaptation time, and behaviour of convergence curve belong among basic properties of adaptive algorithms. L-filters with variety of adaptive algorithms were used to their determination. Convergence performances finding of adaptive filters is important mainly for their hardware applications, where filtration in real time or adaptation of coefficient filter with low capacity of input data are required.

The Globalisation of migration

OpenAIRE

Milan Mesić

2002-01-01

The paper demonstrates that contemporary international migration is a constitutive part of the globalisation process. After defining the concepts of globalisation and the globalisation of migration, the author discusses six key themes, linking globalisation and international migration (“global cities”, the scale of migration; diversification of migration flows; globalisation of science and education; international migration and citizenship; emigrant communities and new identities). First, in ...

Transportation Routing Analysis Geographic Information System -- TRAGIS, progress on improving a routing tool

International Nuclear Information System (INIS)

Johnson, P.E.; Lester, P.B.

1998-05-01

The Transportation Routing Analysis Geographic Information System (TRAGIS) model provides a useful tool to calculate and analyze transportation routes for radioactive materials within the continental US. This paper outlines some of the features available in this model

Collective network routing

Science.gov (United States)

Hoenicke, Dirk

2014-12-02

Disclosed are a unified method and apparatus to classify, route, and process injected data packets into a network so as to belong to a plurality of logical networks, each implementing a specific flow of data on top of a common physical network. The method allows to locally identify collectives of packets for local processing, such as the computation of the sum, difference, maximum, minimum, or other logical operations among the identified packet collective. Packets are injected together with a class-attribute and an opcode attribute. Network routers, employing the described method, use the packet attributes to look-up the class-specific route information from a local route table, which contains the local incoming and outgoing directions as part of the specifically implemented global data flow of the particular virtual network.

Migration and Remittances : Recent Developments and Outlook - Transit Migration

OpenAIRE

World Bank Group

2018-01-01

This Migration and Development Brief reports global trends in migration and remittance flows, as well as developments related to the Global Compact on Migration (GCM), and the Sustainable Development Goal (SDG) indicators for volume of remittances as percentage of gross domestic product (GDP) (SDG indicator 17.3.2), reducing remittance costs (SDG indicator 10.c.1) and recruitment costs (SD...

Advances and Challenges in Convergent Communication Networks

DEFF Research Database (Denmark)

Toral-Cruz, Homero; Mihovska, Albena

2017-01-01

Welcome to this special issue of Wireless Personal Communications on Advances and Challenges in Convergent Communication Networks. The main purpose of this special issue is to present new progresses and challenges in convergent networks. Communication networks play an important role in our daily...... life because they allow communicating and sharing contents between heterogeneous nodes around the globe. The emergence of multiple network architectures and emerging technologies have resulted in new applications and services over a heterogeneous network. This heterogeneous network has undergone...... significant challenges in recent years, such as the evolution to a converged network with the capability to support multiple services, while maintaining a satisfactory level of QoE/QoS, security, efficiency and trust. The special issue on Advances and Challenges in Convergent Communication Networks...

Neutron gain for converging guide tubes

International Nuclear Information System (INIS)

Mildner, D.F.R.

1982-01-01

The method of acceptance diagrams is used to obtain analytical expressions for the neutron gain of a one-dimensional converging guide tube. It is found that the results are more easily expressed by analyzing the acceptance diagram at the exit of the funnel. The results are compared with those for the straight guide. When both guides have the same dimensions at the guide exit, the converging guide has higher transmitted intensity but with greater divergence of the beam. This analytical method is useful to assess the performance of a converging guide, though numerical computations may be required for detailed analysis of a guide system. (orig.)

Convergence

DEFF Research Database (Denmark)

Prasad, Ramjee

2009-01-01

This paper presents the main conclusions which can be drawn from the discussions on Future Communication Systems and lessons on Unpredictable Future of Wireless Communication Systems. Future systems beyond the third generation are already under discussions in international bodies, such as ITU, WW...... and R&D programmes worldwide. The incoming era is characterized by the convergence of networks and access technology and the divergence of applications. Future mobile communication systems should bring something more than only faster data or wireless internet access....

Convergence in energy consumption per capita among ASEAN countries

International Nuclear Information System (INIS)

Mishra, Vinod; Smyth, Russell

2014-01-01

We test for convergence in energy consumption per capita among ASEAN countries over the period 1971 to 2011 using the panel KPSS stationarity test and panel Lagrange multiplier (LM) unit root test. The results for the panel stationarity and unit root tests with structural breaks find support for energy convergence in ASEAN. - Highlights: • We test for convergence in energy consumption per capita among the ASEAN nations. • Univariate conventional unit root tests provide mixed evidence of convergence. • Panel unit root tests with structural breaks support convergence hypothesis

Fuel load and flight ranges of blackcaps Sylvia atricapilla in northern Iberia during autumn and spring migrations

Directory of Open Access Journals (Sweden)

JUAN ARIZAGA, EMILIO BARBA

2009-12-01

Full Text Available Fuel accumulation, mainly as fatty acids, is one of the main characteristics of migratory birds. Studying to what extent each population or species manages fuel load and how it varies along routes of migration or between seasons (autumn and spring migrations is crucial to our understanding of bird migration strategies. Our aim here was to analyse whether migratory blackcaps Sylvia atricapilla passing through northern Iberia differ in their mean fuel loads, rate of fuel accumulation and 'potential' flight ranges between migration seasons. Blackcaps were mist netted for 4 h-periods beginning at dawn from 16 September to 15 November 2003–2005, and from 1 March to 30 April 2004–2006 in a European Atlantic hedgerow at Loza, northern Iberia. Both fuel load and fuel deposition rate (this latter assessed with difference in body mass of within-season recaptured individuals were higher in autumn than in spring. Possible hypotheses explaining these results could be seasonal-associated variations in food availability (likely lower during spring than during autumn, the fact that a fraction of the migrants captured in spring could breed close to the study area and different selective pressures for breeding and wintering [Current Zoology 55 (6: 401–410, 2009].

Route Scherrer and Route Einstein closed for construction work

CERN Multimedia

2015-01-01

Please note that Route Scherrer will be inaccessible for two and a half months from the beginning of March and that part of Route Einstein will be closed for two weeks from the end of February.   Figure 1. The part of Route Scherrer between Building 510 and Building 53 (see Figure 1) will be closed from the beginning of March until mid-May for civil engineering works.   The superheated water pipes supplying the buildings in this area date back to 1959 and therefore present a significant risk of leakage. In order to ensure the reliable supply of superheated water, and, by extension, heating, to all premises near the Main Building (i.e. Buildings 500, 501, 503, 60, 62, 63 and 64), a new buried service duct will be installed between the basements of Buildings 53 and 61 to house a new superheated water pipe. Figure 2. The following car parks will, however, remain accessible for the duration of the works: the Cèdres car park, the car park for Buildings 4 and 5, and the ca...

Highway route controlled quantity shipment routing reports - An overview

International Nuclear Information System (INIS)

Cashwell, J.W.; Welles, B.W.; Welch, M.J.

1989-01-01

US Department of Transportation (DOT) regulations require a postnotification report from the shipper for all shipments of radioactive materials categorized as a Highway Route Controlled Quantity. These postnotification reports, filed in compliance with 49 CFR 172.203(d), have been compiled by the DOT in a database known as the Radioactive Materials Routing Report (RAMRT) since 1982. The data were sorted by each of its elements to establish historical records and trends of Highway Route Controlled Quantity shipments from 1982 through 1987. Approximately 1520 records in the RAMRT database were compiled for this analysis. Approximately half of the shipments reported for the study period were from the US Department of Energy (DOE) and its contractors, with the others being commercial movements. Two DOE installations, EG and G Idaho and Oak Ridge, accounted for nearly half of the DOE activities. Similarly, almost half of the commercial movements were reported by two vendors, Nuclear Assurance Corporation and Transnuclear, Incorporated. Spent fuel from power and research reactors accounted for approximately half of all shipments

US Hazardous Materials Routes, Geographic WGS84, BTS (2006) [hazardous_material_routes_BTS_2006

Data.gov (United States)

Louisiana Geographic Information Center — The Federal Motor Carrier Safety Administration (FMCSA) Hazardous Material Routes were developed using the 2004 First Edition TIGER/Line files. The routes are...

A MODIFIED ROUTE DISCOVERY APPROACH FOR DYNAMIC SOURCE ROUTING (DSR PROTOCOL IN MOBILE AD-HOC NETWORKS

Directory of Open Access Journals (Sweden)

Alaa Azmi Allahham

2017-02-01

Full Text Available Mobile Ad-hoc networks (MANETs involved in many applications, whether commercial or military because of their characteristics that do not depend on the infrastructure as well as the freedom movement of their elements, but in return has caused this random mobility of the nodes many of the challenges, where the routing is considered one of these challenges. There are many types of routing protocols that operate within MANET networks, which responsible for finding paths between the source and destination nodes with the modernization of these paths which are constantly changing due to the dynamic topology of the network stemming from the constant random movement of the nodes. The DSR (Dynamic Source Routing routing protocol algorithm is one of these routing protocols which consist of two main stages; route discovery and maintenance, where the route discovery algorithm operates based on blind flooding of request messages. blind flooding is considered as the most well known broadcasting mechanism, it is inefficient in terms of communication and resource utilization, which causing increasing the probability of collisions, repeating send several copies of the same message, as well as increasing the delay. Hence, a new mechanism in route discovery stage and in caching the routes in DSR algorithm according to the node's location in the network and the direction of the broadcast is proposed for better performance especially in terms of delay as well as redundant packets rate. The implementation of proposed algorithms showed positive results in terms of delay, overhead, and improve the performance of MANETs in general.

Convergence testing for MCNP5 Monte Carlo eigenvalue calculations

International Nuclear Information System (INIS)

Brown, F.; Nease, B.; Cheatham, J.

2007-01-01

Determining convergence of Monte Carlo criticality problems is complicated by the statistical noise inherent in the random, walks of the neutrons in each generation. The latest version of MCNP5 incorporates an important new tool for assessing convergence: the Shannon entropy of the fission source distribution, H src . Shannon entropy is a well-known concept from information theory and provides a single number for each iteration to help characterize convergence trends for the fission source distribution. MCNP5 computes H src for each iteration, and these values may be plotted to examine convergence trends. Convergence testing should include both k eff and H src , since the fission distribution will converge more slowly than k eff , especially when the dominance ratio is close to 1.0. (authors)

Directional migration of leading-edge mesoderm generates physical forces: Implication in Xenopus notochord formation during gastrulation.

Science.gov (United States)

Hara, Yusuke; Nagayama, Kazuaki; Yamamoto, Takamasa S; Matsumoto, Takeo; Suzuki, Makoto; Ueno, Naoto

2013-10-15

Gastrulation is a dynamic tissue-remodeling process occurring during early development and fundamental to the later organogenesis. It involves both chemical signals and physical factors. Although much is known about the molecular pathways involved, the roles of physical forces in regulating cellular behavior and tissue remodeling during gastrulation have just begun to be explored. Here, we characterized the force generated by the leading edge mesoderm (LEM) that migrates preceding axial mesoderm (AM), and investigated the contribution of LEM during Xenopus gastrulation. First, we constructed an assay system using micro-needle which could measure physical forces generated by the anterior migration of LEM, and estimated the absolute magnitude of the force to be 20-80nN. Second, laser ablation experiments showed that LEM could affect the force distribution in the AM (i.e. LEM adds stretch force on axial mesoderm along anterior-posterior axis). Third, migrating LEM was found to be necessary for the proper gastrulation cell movements and the establishment of organized notochord structure; a reduction of LEM migratory activity resulted in the disruption of mediolateral cell orientation and convergence in AM. Finally, we found that LEM migration cooperates with Wnt/PCP to form proper notochord. These results suggest that the force generated by the directional migration of LEM is transmitted to AM and assists the tissue organization of notochord in vivo independently of the regulation by Wnt/PCP. We propose that the LEM may have a mechanical role in aiding the AM elongation through the rearrangement of force distribution in the dorsal marginal zone. © 2013 Elsevier Inc. All rights reserved.

Route-specific analysis for radioactive materials transportation

International Nuclear Information System (INIS)

1986-01-01

This report addresses a methodology for route-specific analysis, of which route-selection is one aspect. Identification and mitigation of specific hazards along a chosen route is another important facet of route-specific analysis. Route-selection and route-specific mitigation are two tools to be used in minimizing the risk of radioactive materials transportation and promoting public confidence. Other tools exist to improve the safety of transportation under the Nuclear Waste Policy Act. Selection of a transportation mode and other, non-route-specific measures, such as improved driver training and improved cask designs, are additional tools to minimize transportation risk and promote public confidence. This report addresses the route-specific analysis tool and does not attempt to evaluate its relative usefulness as compared to other available tools. This report represents a preliminary attempt to develop a route-specific analysis methodlogy. The Western Interstate Energy Board High-Level Waste Committee has formed a Route-Specific Analysis Task Force which will build upon the methodology proposed in this Staff Report. As western states continue to investigate route-specific analysis issues, it is expected that the methodology will evolve into a more refined product representing the views of a larger group of interested parties in the West

Bellman Ford algorithm - in Routing Information Protocol (RIP)

Science.gov (United States)

Krianto Sulaiman, Oris; Mahmud Siregar, Amir; Nasution, Khairuddin; Haramaini, Tasliyah

2018-04-01

In a large scale network need a routing that can handle a lot number of users, one of the solutions to cope with large scale network is by using a routing protocol, There are 2 types of routing protocol that is static and dynamic, Static routing is manually route input based on network admin, while dynamic routing is automatically route input formed based on existing network. Dynamic routing is efficient used to network extensively because of the input of route automatic formed, Routing Information Protocol (RIP) is one of dynamic routing that uses the bellman-ford algorithm where this algorithm will search for the best path that traversed the network by leveraging the value of each link, so with the bellman-ford algorithm owned by RIP can optimize existing networks.

Irregular Migration flows and human trafficking in the Western Balkan countries: challenges of the covergence of counter-trafficking response

OpenAIRE

Mece, Merita H.

2016-01-01

Irregular migration on the Western Balkan route has marked an unprecedented number during the last five years. Evidence indicates that both, non-European nationals and Western Balkan citizens have been involved in this complex migratory flow being exposed to various risks of human trafficking. But Western Balkan countries are source, transit and destination countries of human trafficking while their states are not well organized to implement a comprehensive and well-coordinated regional respo...

Digital Convergence and Content Regulation

Directory of Open Access Journals (Sweden)

Michael John Starks

2014-12-01

Full Text Available Broadcasting, Press and Internet journalism systems of distribution are converging: the same infrastructure can deliver all three historically separate services. Reception devices mirror this: the Connected TV, the tablet and the smart phone overlap in their functionality. Service overlaps are evident too, with broadcasters providing online and on-demand services and newspapers developing electronic versions. Does this mean that media regulation policies must converge too?My argument is that they should, though only where historically different communications are now fulfilling a similar function, e.g. broadcaster online services and electronic versions of newspapers. Convergence requires a degree of harmonisation and, to this end, I advocate a review of UK broadcasting's 'due impartiality' requirement and of the UK's application of the public service concept. I also argue for independent self-regulation (rather than state-based regulation of non-public-service broadcasting journalism.

Population, migration and urbanization.

Science.gov (United States)

1982-06-01

Despite recent estimates that natural increase is becoming a more important component of urban growth than rural urban transfer (excess of inmigrants over outmigrants), the share of migration in the total population growth has been consistently increasing in both developed and developing countries. From a demographic perspective, the migration process involves 3 elements: an area of origin which the mover leaves and where he or she is considered an outmigrant; the destination or place of inmigration; and the period over which migration is measured. The 2 basic types of migration are internal and international. Internal migration consists of rural to urban migration, urban to urban migration, rural to rural migration, and urban to rural migration. Among these 4 types of migration various patterns or processes are followed. Migration may be direct when the migrant moves directly from the village to the city and stays there permanently. It can be circular migration, meaning that the migrant moves to the city when it is not planting season and returns to the village when he is needed on the farm. In stage migration the migrant makes a series of moves, each to a city closer to the largest or fastest growing city. Temporary migration may be 1 time or cyclical. The most dominant pattern of internal migration is rural urban. The contribution of migration to urbanization is evident. For example, the rapid urbanization and increase in urban growth from 1960-70 in the Republic of Korea can be attributed to net migration. In Asia the largest component of the population movement consists of individuals and groups moving from 1 rural location to another. Recently, because urban centers could no longer absorb the growing number of migrants from other places, there has been increased interest in the urban to rural population redistribution. This reverse migration also has come about due to slower rates of employment growth in the urban centers and improved economic opportunities

Rates of convergence of Brezier net over triangles

International Nuclear Information System (INIS)

Feng Yuyu.

1986-12-01

It is well known (Farin, 1979) that the sequence of Bezier nets f-circumflex n (x) associated with Bernstein-Bezier surface over a triangle converges to the surface uniformly as n goes to infinity. In this paper the precise rates of convergence are given. The pointwise convergence result and saturation theorem are presented. (author). 7 refs

Evolution and convergence in telecommunications

Energy Technology Data Exchange (ETDEWEB)

Radicella, S; Grilli, D [Abdus Salam ICTP, Trieste (Italy)

2002-12-15

These lectures throw a spotlight on different aspects of the evolution of telecommunications networks, namely on the various facets of service and network convergence. The last years progress in data and telecommunications technologies, such as P-based networks, and the enormous potential of mobile communication systems and users' demands for comprehensive and network-independent have led to a convergence of data and telecommunications infrastructures in many aspects. In order to help the reader to an easier understanding of the phenomenon convergence, in the first two parts of this volume the evolution of the basic technologies is described one by one. This is done briefly and is focused on the principle topics, just to build a basis for the third part devoted to problems of convergence in telecommunications. These notes are addressed to those readers, who in a quick overview want to be informed on the future service and network landscape. The notes are equally suited for professionals with the desire to extend their horizon as well as for students looking for an introduction into telecommunications under more general aspects. The authors clearly understand the difficulties in writing a book devoted to the evolution in telecommunications. Today, telecom landscape varies at very high speed. Every few months new network technologies, new products and new services are developed. Attempts to present them in time can be accessible only for magazine publications or contributions to conferences. Therefore, in a number of areas, such as Voice over IP and new switching technologies not much more than the starting point of new paradigms is described. However, the content is up-to-date to a degree, that the phenomenon convergence can be fully understood. Partially, these notes are based on a number of lecture courses that were delivered during recent ICTP winter schools devoted to multimedia and digital communications.

Evolution and convergence in telecommunications

International Nuclear Information System (INIS)

Radicella, S.; Grilli, D.

2002-01-01

These lectures throw a spotlight on different aspects of the evolution of telecommunications networks, namely on the various facets of service and network convergence. The last years progress in data and telecommunications technologies, such as P-based networks, and the enormous potential of mobile communication systems and users' demands for comprehensive and network-independent have led to a convergence of data and telecommunications infrastructures in many aspects. In order to help the reader to an easier understanding of the phenomenon convergence, in the first two parts of this volume the evolution of the basic technologies is described one by one. This is done briefly and is focused on the principle topics, just to build a basis for the third part devoted to problems of convergence in telecommunications. These notes are addressed to those readers, who in a quick overview want to be informed on the future service and network landscape. The notes are equally suited for professionals with the desire to extend their horizon as well as for students looking for an introduction into telecommunications under more general aspects. The authors clearly understand the difficulties in writing a book devoted to the evolution in telecommunications. Today, telecom landscape varies at very high speed. Every few months new network technologies, new products and new services are developed. Attempts to present them in time can be accessible only for magazine publications or contributions to conferences. Therefore, in a number of areas, such as Voice over IP and new switching technologies not much more than the starting point of new paradigms is described. However, the content is up-to-date to a degree, that the phenomenon convergence can be fully understood. Partially, these notes are based on a number of lecture courses that were delivered during recent ICTP winter schools devoted to multimedia and digital communications

Predicting transportation routes for radioactive wastes

International Nuclear Information System (INIS)

Joy, D.S.; Johnson, P.E.; Clarke, D.B.; McGuire, S.C.

1981-01-01

Oak Ridge National Laboratory (ORNL) has been involved in transportation logistics of radioactive wastes as part of the overall waste transportation program. A Spent Fuel Logistics Model (SFLM), was developed to predict overall material balances representing the flow of spent fuel assemblies from reactors to away-from-reactor storage facilities and/or to federal repositories. The transportation requirements to make these shipments are also itemized. The next logical step in the overall transportation project was the development of a set of computer codes which would predict likely transportation routes for waste shipments. Two separate routing models are now operational at ORNL. Routes for truck transport can be estimated with the HIGHWAY program, and rail and barge routes can be predicted with the INTERLINE model. This paper discusses examples of the route estimates and applications of the routing models

Signaling through three chemokine receptors triggers the migration of transplanted neural precursor cells in a model of multiple sclerosis.

Science.gov (United States)

Cohen, Mikhal E; Fainstein, Nina; Lavon, Iris; Ben-Hur, Tamir

2014-09-01

Multiple sclerosis (MS) is a multifocal disease, and precursor cells need to migrate into the multiple lesions in order to exert their therapeutic effects. Therefore, cell migration is a crucial element in regenerative processes in MS, dictating the route of delivery, when cell transplantation is considered. We have previously shown that inflammation triggers migration of multi-potential neural precursor cells (NPCs) into the white matter of experimental autoimmune encephalomyelitis (EAE) rodents, a widely used model of MS. Here we investigated the molecular basis of this attraction. NPCs were grown from E13 embryonic mouse brains and transplanted into the lateral cerebral ventricles of EAE mice. Transplanted NPC migration was directed by three tissue-derived chemokines. Stromal cell-derived factor-1α, monocyte chemo-attractant protein-1 and hepatocyte growth factor were expressed in the EAE brain and specifically in microglia and astrocytes. Their cognate receptors, CXCR4, CCR2 or c-Met were constitutively expressed on NPCs. Selective blockage of CXCR4, CCR2 or c-Met partially inhibited NPC migration in EAE brains. Blocking all three receptors had an additive effect and resulted in profound inhibition of NPC migration, as compared to extensive migration of control NPCs. The inflammation-triggered NPC migration into white matter tracts was dependent on a motile NPC phenotype. Specifically, depriving NPCs from epidermal growth factor (EGF) prevented the induction of glial commitment and a motile phenotype (as indicated by an in vitro motility assay), hampering their response to neuroinflammation. In conclusion, signaling via three chemokine systems accounts for most of the inflammation-induced, tissue-derived attraction of transplanted NPCs into white matter tracts during EAE. Copyright © 2014. Published by Elsevier B.V.

Harmonisation of European Migration Policies: The Failure of Immigration Control Policies in the Seventh and Eighth Decades of the 20th Century

Directory of Open Access Journals (Sweden)

Milan Mesić

2003-12-01

Full Text Available Until the middle of the 1970s, the migration policies of developed European countries were based on the assumption that controlling immigration was possible. Due to various reasons discussed in this article, such policies proved unsuccessful. The result was an increase in the total number of foreigners and a change in the composition of immigrant communities, i.e. the proportion of supported family members increased. During the 1980s there was increasing convergence in the migration policies of European immigration countries and traditional overseas emigration countries. Policies were more and more oriented towards preventing illegal migration flows, on regulating refugee flows and on balancing labour migration with family migration. The turning-point in the direction of “harmonising” West European migration policies was marked by the Schengen agreement (1985 on gradual elimination of border controls between the signing parties (France, Germany and the Benelux countries. Fear in the face of a possible invasion of Eastern Europeans after the collapse of socialism in 1989 was a further strong stimulus towards the harmonisation of migration policies in the developing EU. As opposed to migration control, the integration of immigrants has remained so far the prerogative of nation-states. The text further presents an overview of migration policy reforms in individual member states of the EU and of multilateral actions. The post-1989 migration regime in Europe has four major traits: 1 an extension of the agenda; 2 an accent on joint actions; 3 defensiveness; 4 confusion and an overload of issues. While on the one hand the EU continues to seek ways of protecting itself from undesired external migration, on the other hand the process of regional integration continues to “erase” its internal borders.

Specialisation and Convergence in European Regions

Directory of Open Access Journals (Sweden)

Enrico Marelli

2007-09-01

Full Text Available The purpose of this paper was to analyze specialization and convergence of European countries and regions, within the framework of integration in the EU. This is important not only for long-term real convergence processes, but also for a proper functioning of the monetary union (in the line of research on the OCA's criteria, asymmetry of shocks and synchronization of business cycles. The position of new member states is particularly delicate, also considering the forthcoming adoption of the euro by some of them. As indicated by the EU Treaty, economic growth should be balanced with economic and social cohesion that includes a careful consideration of regional disparities. Our empirical investigation focuses on the regions of EU25, further broken up into other relevant groupings (EU15, EMU, and the new members' EU10 group, over the period from 1980 (or 1990 for EU10 to 2005. This paper considers a rather fine regional disaggregation (NUTS-2 level, counting 250 regions. The analysis of different indices of specialisation point to a prevalent increase of homogeneity of sector structures across European regions, although in some cases (especially in the industrial sector and in some services specialisation has increased. For convergence, a sigma convergence's analysis confirms a reduction of disparities, both at a country and regional level. However, a trade-off between fast national growth and internal distribution has emerged in the early stages of development, as in the case of new members. Moreover, beta convergence has also been established - regarding per capita income, employment and productivity - for almost all territorial aggregates (excluding the new members since 1999. The addition of structural variables, following a beta-conditional approach, indicates a positive role for services and a negative impact of agriculture. Finally, some preliminary results have been obtained by the innovative inclusion of specialisation indices within

In vivo migration of labeled autologous natural killer cells to liver metastases in patients with colon carcinoma

Directory of Open Access Journals (Sweden)

Satolli Maria A

2006-11-01

Full Text Available Abstract Background Besides being the effectors of native anti-tumor cytotoxicity, NK cells participate in T-lymphocyte responses by promoting the maturation of dendritic cells (DC. Adherent NK (A-NK cells constitute a subset of IL-2-stimulated NK cells which show increased expression of integrins and the ability to adhere to solid surface and to migrate, infiltrate, and destroy cancer. A critical issue in therapy of metastatic disease is the optimization of NK cell migration to tumor tissues and their persistence therein. This study compares localization to liver metastases of autologous A-NK cells administered via the systemic (intravenous, i.v. versus locoregional (intraarterial, i.a. routes. Patients and methods A-NK cells expanded ex-vivo with IL-2 and labeled with 111In-oxine were injected i.a. in the liver of three colon carcinoma patients. After 30 days, each patient had a new preparation of 111In-A-NK cells injected i.v. Migration of these cells to various organs was evaluated by SPET and their differential localization to normal and neoplastic liver was demonstrated after i.v. injection of 99mTc-phytate. Results A-NK cells expressed a donor-dependent CD56+CD16+CD3- (NK or CD56+CD16+CD3+ (NKT phenotype. When injected i.v., these cells localized to the lung before being visible in the spleen and liver. By contrast, localization of i.a. injected A-NK cells was virtually confined to the spleen and liver. Binding of A-NK cells to liver neoplastic tissues was observed only after i.a. injections. Conclusion This unique study design demonstrates that A-NK cells adoptively transferred to the liver via the intraarterial route have preferential access and substantial accumulation to the tumor site.

RSRP: A Robust Secure Routing Protocol in MANET

Directory of Open Access Journals (Sweden)

Sinha Ditipriya

2014-05-01

Full Text Available In this paper, we propose a novel algorithm RSRP to build a robust secure routing protocol in mobile ad-hoc networks (MANETs. This algorithm is based on some basic schemes such as RSA_CRT for encryption and decryption of messages; CRT for safety key generation, Shamir’s secret sharing principle for generation of secure routes. Those routes which are free from any malicious node and which belong to the set of disjoint routes between a source-destination pair are considered as probable routes. Shamir’s secret sharing principle is applied on those probable routes to obtain secure routes. Finally, most trustworthy and stable route is selected among those secure routes. Selection of the final route depends on some criteria of the nodes present in a route e.g.: battery power, mobility and trust value. In addition, complexity of key generation is reduced to a large extent by using RSA-CRT instead of RSA. In turn, the routing becomes less expensive and most secure and robust one. Performance of this routing protocol is then compared with non-secure routing protocols (AODV and DSR, secure routing scheme using secret sharing, security routing protocol using ZRP and SEAD depending on basic characteristics of these protocols. All such comparisons show that RSRP shows better performance in terms of computational cost, end-to-end delay and packet dropping in presence of malicious nodes in the MANET, keeping the overhead in terms of control packets same as other secure routing protocols.

Human risk assessment of dermal and inhalation exposures to chemicals assessed by route-to-route extrapolation: the necessity of kinetic data.

Science.gov (United States)

Geraets, Liesbeth; Bessems, Jos G M; Zeilmaker, Marco J; Bos, Peter M J

2014-10-01

In toxicity testing the oral route is in general the first choice. Often, appropriate inhalation and dermal toxicity data are absent. Risk assessment for these latter routes usually has to rely on route-to-route extrapolation starting from oral toxicity data. Although it is generally recognized that the uncertainties involved are (too) large, route-to-route extrapolation is applied in many cases because of a strong need of an assessment of risks linked to a given exposure scenario. For an adequate route-to-route extrapolation the availability of at least some basic toxicokinetic data is a pre-requisite. These toxicokinetic data include all phases of kinetics, from absorption (both absorbed fraction and absorption rate for both the starting route and route of interest) via distribution and biotransformation to excretion. However, in practice only differences in absorption between the different routes are accounted for. The present paper demonstrates the necessity of route-specific absorption data by showing the impact of its absence on the uncertainty of the human health risk assessment using route-to-route extrapolation. Quantification of the absorption (by in vivo, in vitro or in silico methods), particularly for the starting route, is considered essential. Copyright © 2014 Elsevier Inc. All rights reserved.

Radon depth migration

International Nuclear Information System (INIS)

Hildebrand, S.T.; Carroll, R.J.

1993-01-01

A depth migration method is presented that used Radon-transformed common-source seismograms as input. It is shown that the Radon depth migration method can be extended to spatially varying velocity depth models by using asymptotic ray theory (ART) to construct wavefield continuation operators. These operators downward continue an incident receiver-array plane wave and an assumed point-source wavefield into the subsurface. The migration velocity model is constrain to have longer characteristic wavelengths than the dominant source wavelength such that the ART approximations for the continuation operators are valid. This method is used successfully to migrate two synthetic data examples: (1) a point diffractor, and (2) a dipping layer and syncline interface model. It is shown that the Radon migration method has a computational advantage over the standard Kirchhoff migration method in that fewer rays are computed in a main memory implementation

Fractal aspects and convergence of Newton`s method

Energy Technology Data Exchange (ETDEWEB)

Drexler, M. [Oxford Univ. Computing Lab. (United Kingdom)

1996-12-31

Newton`s Method is a widely established iterative algorithm for solving non-linear systems. Its appeal lies in its great simplicity, easy generalization to multiple dimensions and a quadratic local convergence rate. Despite these features, little is known about its global behavior. In this paper, we will explain a seemingly random global convergence pattern using fractal concepts and show that the behavior of the residual is entirely explicable. We will also establish quantitative results for the convergence rates. Knowing the mechanism of fractal generation, we present a stabilization to the orthodox Newton method that remedies the fractal behavior and improves convergence.

Vehicle Routing With User Generated Trajectory Data

DEFF Research Database (Denmark)

Ceikute, Vaida; Jensen, Christian S.

Rapidly increasing volumes of GPS data collected from vehicles provide new and increasingly comprehensive insight into the routes that drivers prefer. While routing services generally compute shortest or fastest routes, recent studies suggest that local drivers often prefer routes that are neithe...

Revisiting convergence: A research note.

Science.gov (United States)

Clark, Rob

2015-09-01

A number of recent studies show that income inequality is declining between countries. In this research note, I question the significance of this trend by examining the role of initial conditions in producing convergence. An important (but neglected) property of inequality dynamics is the tendency for extreme distributions to become more moderate. When income disparities are large, the subsequent trend is biased toward convergence. Conversely, when initial conditions approach parity, divergence becomes the more likely long-term outcome. I apply this principle to trends in GDP PC across 127 countries during the 1980-2010 period. Using counterfactual analysis, I manipulate the initial level of inequality in GDP PC while holding constant each country's observed growth rate during the sample period. I find that the growth dynamics of GDP PC produce either convergence or divergence based simply on the initial distribution of income. The point of transition occurs at a moderate level of inequality, whether using population weights (Gini=.365) or not (Gini=.377). I conclude that the recent convergence observed in GDP PC is primarily a function of large income gaps between countries and would not have materialized at more moderate levels of initial inequality. By contrast, an examination of the pre-1950 period reveals divergent growth patterns that are not sensitive to initial conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

A Genetic Algorithm on Inventory Routing Problem

Directory of Open Access Journals (Sweden)

Nevin Aydın

2014-03-01

Full Text Available Inventory routing problem can be defined as forming the routes to serve to the retailers from the manufacturer, deciding on the quantity of the shipment to the retailers and deciding on the timing of the replenishments. The difference of inventory routing problems from vehicle routing problems is the consideration of the inventory positions of retailers and supplier, and making the decision accordingly. Inventory routing problems are complex in nature and they can be solved either theoretically or using a heuristics method. Metaheuristics is an emerging class of heuristics that can be applied to combinatorial optimization problems. In this paper, we provide the relationship between vendor-managed inventory and inventory routing problem. The proposed genetic for solving vehicle routing problem is described in detail.

Theoretical foundations of international migration process studies: analysis of key migration theories development

Directory of Open Access Journals (Sweden)

Shymanska K.V.

2017-03-01

Full Text Available The need for transformation of Ukraine's migration policy based on globalized world development trends and in response to the challenges of European integration transformations causes the need of researching the theoretical and methodological basis of migration studies, and the regulations of existing theories of international migration. The bibliometric analysis of scientific publications on international migration in cites indexes found that the recent researches on these problems acquire interdisciplinary character. It necessitates the transformation of migration study approaches basing on economic, social, institutional theories and concepts synthesis. The article is devoted to the study of theoretical regulations of existing international migration theories in the context of the evolution of scientists’ views on this phenomenon. The author found that the existing theories of international migration should be divided into three categories (microeconomic, macroeconomic, globalizational that contributes to their understanding in the context of implementation possibilities in migrational public administration practice. It allows to determine the theories which should be used for Ukrainian state migration policy constructing and eliminating or reducing the external migration negative effects.

Is the environmental performance of industrialized countries converging? A 'SURE' approach to testing for convergence

International Nuclear Information System (INIS)

Camarero, Mariam; Picazo-Tadeo, Andres J.; Tamarit, Cecilio

2008-01-01

In this paper, we test for convergence in the environmental performance of a sample of OECD countries, with data ranging from 1971 to 2002. First, we use Data Envelopment Analysis (DEA) to compute two environmental performance indicators (EPIs) in the production theory framework. Second, we propose the use of a sequential multivariate approach to test for convergence in environmental performance. These tests allow us to reconcile the time series literature with the cross-sectional dimension, which is basic when testing for convergence in regional blocs. The SURE technique is used, which allows for the existence of correlations across the series without imposing a common speed of mean reversion. The empirical results show that the group of countries as a whole, as well as the majority of countries considered on an individual basis (results for some countries vary between EPIs), are catching-up with Switzerland (the benchmark country). (author)

Reduced vergence adaptation is associated with a prolonged output of convergence accommodation in convergence insufficiency.

Science.gov (United States)

Sreenivasan, Vidhyapriya; Bobier, William R

2014-07-01

Convergence insufficiency (CI) is a developmental visual anomaly defined clinically by a reduced near point of convergence, a reduced capacity to view through base-out prisms (fusional convergence); coupled with asthenopic symptoms typically blur and diplopia. Experimental studies show reduced vergence parameters and tonic adaptation. Based upon current models of accommodation and vergence, we hypothesize that the reduced vergence adaptation in CI leads to excessive amounts of convergence accommodation (CA). Eleven CI participants (mean age=17.4±2.3 years) were recruited with reduced capacity to view through increasing magnitudes of base out (BO) prisms (mean fusional convergence at 40 cm=12±0.9Δ). Testing followed our previous experimental design for (n=11) binocularly normal adults. Binocular fixation of a difference of Gaussian (DoG) target (0.2 cpd) elicited CA responses during vergence adaptation to a 12Δ BO. Vergence and CA responses were obtained at 3 min intervals over a 15 min period and time course were quantified using exponential decay functions. Results were compared to previously published data on eleven binocular normals. Eight participants completed the study. CI's showed significantly reduced magnitude of vergence adaptation (CI: 2.9Δ vs. normals: 6.6Δ; p=0.01) and CA reduction (CI=0.21 D, Normals=0.55 D; p=0.03). However, the decay time constants for adaptation and CA responses were not significantly different. CA changes were not confounded by changes in tonic accommodation (Change in TA=0.01±0.2D; p=0.8). The reduced magnitude of vergence adaptation found in CI patients resulting in higher levels of CA may potentially explain their clinical findings of reduced positive fusional vergence (PFV) and the common symptom of blur. Copyright © 2014 Elsevier B.V. All rights reserved.

Zone routing in a torus network

Science.gov (United States)

Chen, Dong; Heidelberger, Philip; Kumar, Sameer

2013-01-29

A system for routing data in a network comprising a network logic device at a sending node for determining a path between the sending node and a receiving node, wherein the network logic device sets one or more selection bits and one or more hint bits within the data packet, a control register for storing one or more masks, wherein the network logic device uses the one or more selection bits to select a mask from the control register and the network logic device applies the selected mask to the hint bits to restrict routing of the data packet to one or more routing directions for the data packet within the network and selects one of the restricted routing directions from the one or more routing directions and sends the data packet along a link in the selected routing direction toward the receiving node.

Migration and risk: net migration in marginal ecosystems and hazardous areas

International Nuclear Information System (INIS)

De Sherbinin, Alex; Levy, Marc; Adamo, Susana; MacManus, Kytt; Yetman, Greg; Mara, Valentina; Razafindrazay, Liana; Aichele, Cody; Pistolesi, Linda; Goodrich, Benjamin; Srebotnjak, Tanja

2012-01-01

The potential for altered ecosystems and extreme weather events in the context of climate change has raised questions concerning the role that migration plays in either increasing or reducing risks to society. Using modeled data on net migration over three decades from 1970 to 2000, we identify sensitive ecosystems and regions at high risk of climate hazards that have seen high levels of net in-migration and out-migration over the time period. This paper provides a literature review on migration related to ecosystems, briefly describes the methodology used to develop the estimates of net migration, then uses those data to describe the patterns of net migration for various ecosystems and high risk regions. The study finds that negative net migration generally occurs over large areas, reflecting its largely rural character, whereas areas of positive net migration are typically smaller, reflecting its largely urban character. The countries with largest population such as China and India tend to drive global results for all the ecosystems found in those countries. Results suggest that from 1970 to 2000, migrants in developing countries have tended to move out of marginal dryland and mountain ecosystems and out of drought-prone areas, and have moved towards coastal ecosystems and areas that are prone to floods and cyclones. For North America results are reversed for dryland and mountain ecosystems, which saw large net influxes of population in the period of record. Uncertainties and potential sources of error in these estimates are addressed. (letter)

Capacity Constrained Routing Algorithms for Evacuation Route Planning

National Research Council Canada - National Science Library

Lu, Qingsong; George, Betsy; Shekhar, Shashi

2006-01-01

.... In this paper, we propose a new approach, namely a capacity constrained routing planner which models capacity as a time series and generalizes shortest path algorithms to incorporate capacity constraints...

Migration challenges among Zimbabwean refugees before, during and post arrival in South Africa

Directory of Open Access Journals (Sweden)

Erhabor Sunday Idemudia

2013-01-01

Full Text Available BACKGROUND: Zimbabweans are immigrating to South Africa with a commonly cited reason being economic opportunities. Prospects of finding employment may be a significant reason to leave behind family, friends, and community, sources that buffer and offer social support against life’s challenges. Currently, there is a dearth of research examining the motivators for Zimbabweans immigrating and the experiences encountered along the way and after arrival in South Africa. Such research is essential as large numbers of Zimbabweans may be at risk for emotional and physical trauma during this process. METHODS: Two gender specific focus group discussions, each lasting 90-minutes and consisting of homeless Zimbabwean refugees, were conducted in the Limpopo Province of South Africa. A semi-structured interview assessed for experiences in and reasons for leaving Zimbabwe, as well as experiences en-route and within South Africa. Discussions were audio-recorded, transcribed, and analyzed using consensual qualitative research and a constant comparison qualitative method. RESULTS: Three temporal themes were identified and included challenges and trauma experienced in Zimbabwe (pre-migration, during the immigration journey (mid-migration, and upon arrival in South Africa (post-migration. While there were some experiential differences, Zimbabwean men and women shared numerous traumatic commonalities. In addition to the themes, three subthemes contributing to reasons for leaving Zimbabwe, two subthemes of negative and traumatic experiences incurred mid-migration, and two post-migration subthemes of challenges were identified. CONCLUSIONS: Despite the difficulties encountered in their homeland, newly arrived Zimbabweans in South Africa may be exchanging old struggles for a new array of foreign and traumatic challenges. Reasons to immigrate and the psychological and physical toll of migration exacted at the individual and community levels are discussed

Migratory timing, rate, routes and wintering areas of White-crested Elaenia (Elaenia albiceps chilensis, a key seed disperser for Patagonian forest regeneration.

Directory of Open Access Journals (Sweden)

Susana Patricia Bravo

Full Text Available Migratory animals often play key ecological roles within the communities they visit throughout their annual journeys. As a consequence of the links between biomes mediated by migrants, changes in one biome could affect remote areas in unpredictable ways. Migratory routes and timing of most Neotropical austral migrants, which breed at south temperate latitudes of South America and overwinter closer to or within tropical latitudes of South America, have yet to be described in detail. As a result, our understanding about how these birds provide links between South American biomes is almost non-existent. White-crested Elaenia (Elaenia albiceps chilensis is a long-distance austral migrant that breeds in the Patagonian Forest biome and overwinters in tropical South America. Because this small flycatcher plays a key role in the regeneration of this ecosystem, our objective was to describe the annual cycle of White-crested elaenias to evaluate the degree of migratory connectivity between breeding and wintering areas and therefore to determine if there are specific biomes of northern South America linked by elaenias to Patagonian forests. Fifteen individuals were successfully tracked throughout a complete migration cycle using miniature light-level geolocators. All individuals resided and moved through the same general regions. During fall (March-April-May, elaenias were located in the Caatinga and the Atlantic Forest biomes, from Rio de Janeiro to the region near Salvador da Bahia, Brazil. During winter (June-July-Aug., birds were located further inland, within the Cerrado biome. Birds used three different routes during fall migration. Our results indicate that some individuals use a direct route, flying between 500-600 km/day, crossing desert and grasslands, while others took a detour, flying 100-200 km/day through forested areas with refueling opportunities. All birds used the Yunga forest during spring migration, with ten out of 15 individuals

Neuronal Migration and Neuronal Migration Disorder in Cerebral Cortex

OpenAIRE

SUN, Xue-Zhi; TAKAHASHI, Sentaro; GUI, Chun; ZHANG, Rui; KOGA, Kazuo; NOUYE, Minoru; MURATA, Yoshiharu

2002-01-01

Neuronal cell migration is one of the most significant features during cortical development. After final mitosis, neurons migrate from the ventricular zone into the cortical plate, and then establish neuronal lamina and settle onto the outermost layer, forming an "inside-out" gradient of maturation. Neuronal migration is guided by radial glial fibers and also needs proper receptors, ligands, and other unknown extracellular factors, requests local signaling (e.g. some emitted by the Cajal-Retz...

Post-convergence automatic differentiation of iterative schemes

International Nuclear Information System (INIS)

Azmy, Y.Y.

1997-01-01

A new approach for performing automatic differentiation (AD) of computer codes that embody an iterative procedure, based on differentiating a single additional iteration upon achieving convergence, is described and implemented. This post-convergence automatic differentiation (PAD) technique results in better accuracy of the computed derivatives, as it eliminates part of the derivatives convergence error, and a large reduction in execution time, especially when many iterations are required to achieve convergence. In addition, it provides a way to compute derivatives of the converged solution without having to repeat the entire iterative process every time new parameters are considered. These advantages are demonstrated and the PAD technique is validated via a set of three linear and nonlinear codes used to solve neutron transport and fluid flow problems. The PAD technique reduces the execution time over direct AD by a factor of up to 30 and improves the accuracy of the derivatives by up to two orders of magnitude. The PAD technique's biggest disadvantage lies in the necessity to compute the iterative map's Jacobian, which for large problems can be prohibitive. Methods are discussed to alleviate this difficulty

Entanglement-Gradient Routing for Quantum Networks.

Science.gov (United States)

Gyongyosi, Laszlo; Imre, Sandor

2017-10-27

We define the entanglement-gradient routing scheme for quantum repeater networks. The routing framework fuses the fundamentals of swarm intelligence and quantum Shannon theory. Swarm intelligence provides nature-inspired solutions for problem solving. Motivated by models of social insect behavior, the routing is performed using parallel threads to determine the shortest path via the entanglement gradient coefficient, which describes the feasibility of the entangled links and paths of the network. The routing metrics are derived from the characteristics of entanglement transmission and relevant measures of entanglement distribution in quantum networks. The method allows a moderate complexity decentralized routing in quantum repeater networks. The results can be applied in experimental quantum networking, future quantum Internet, and long-distance quantum communications.

Japanese Migration and the Americas: An Introduction to the Study of Migration.

Science.gov (United States)

Mukai, Gary; Brunette, Rachel

This curriculum module introduces students to the study of migration, including a brief overview of some categories of migration and reasons why people migrate. As a case study, the module uses the Japanese migration experience in the United States, Peru, Brazil, Canada, Mexico, Argentina, Bolivia, and Paraguay. The module introduces students to…

The Pyramidal Capacitated Vehicle Routing Problem

DEFF Research Database (Denmark)

Lysgaard, Jens

This paper introduces the Pyramidal Capacitated Vehicle Routing Problem (PCVRP) as a restricted version of the Capacitated Vehicle Routing Problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the Pyramidal Traveling Salesman Problem (PTSP). A pyramidal...

The pyramidal capacitated vehicle routing problem

DEFF Research Database (Denmark)

Lysgaard, Jens

2010-01-01

This paper introduces the pyramidal capacitated vehicle routing problem (PCVRP) as a restricted version of the capacitated vehicle routing problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the pyramidal traveling salesman problem (PTSP). A pyramidal...

Well-Tempered Metadynamics Converges Asymptotically

Science.gov (United States)

Dama, James F.; Parrinello, Michele; Voth, Gregory A.

2014-06-01

Metadynamics is a versatile and capable enhanced sampling method for the computational study of soft matter materials and biomolecular systems. However, over a decade of application and several attempts to give this adaptive umbrella sampling method a firm theoretical grounding prove that a rigorous convergence analysis is elusive. This Letter describes such an analysis, demonstrating that well-tempered metadynamics converges to the final state it was designed to reach and, therefore, that the simple formulas currently used to interpret the final converged state of tempered metadynamics are correct and exact. The results do not rely on any assumption that the collective variable dynamics are effectively Brownian or any idealizations of the hill deposition function; instead, they suggest new, more permissive criteria for the method to be well behaved. The results apply to tempered metadynamics with or without adaptive Gaussians or boundary corrections and whether the bias is stored approximately on a grid or exactly.

Routed planar networks

Directory of Open Access Journals (Sweden)

David J. Aldous

2016-04-01

Full Text Available Modeling a road network as a planar graph seems very natural. However, in studying continuum limits of such networks it is useful to take {\\em routes} rather than {\\em edges} as primitives. This article is intended to introduce the relevant (discrete setting notion of {\\em routed network} to graph theorists. We give a naive classification of all 71 topologically different such networks on 4 leaves, and pose a variety of challenging research questions.

Semi-convergence properties of Kaczmarz’s method

DEFF Research Database (Denmark)

Elfving, Tommy; Hansen, Per Christian; Nikazad, Touraj

2014-01-01

Kaczmarz’s method—sometimes referred to as the algebraic reconstruction technique—is an iterative method that is widely used in tomographic imaging due to its favorable semi-convergence properties. Specifically, when applied to a problem with noisy data, during the early iterations it converges......-convergence of Kaczmarz’s method as well as its projected counterpart (and their block versions). To do this we study how the data errors propagate into the iteration vectors and we derive upper bounds for this noise propagation. Our bounds are compared with numerical results obtained from tomographic imaging....

[Internal migration studies].

Science.gov (United States)

Stpiczynski, T

1986-10-01

Recent research on internal migration in Poland is reviewed. The basic sources of data, consisting of censuses or surveys, are first described. The author discusses the relationship between migration studies and other sectors of the national economy, and particularly the relationship between migration and income.

The apparent and effective chloride migration coefficients obtained in migration tests

NARCIS (Netherlands)

Spiesz, P.R.; Brouwers, H.J.H.

2013-01-01

The apparent (Dapp) and effective (Deff) migration coefficients obtained in chloride migration tests are investigated in this study. The presented Dapp profiles in concrete show that the apparent migration coefficient is strongly concentration-dependent. As demonstrated, the binding of chlorides is

Road Routes for Waste Disposal - MDC_RecyclingRoute

Data.gov (United States)

NSGIC Local Govt | GIS Inventory — This CURBSIDE RECYCLING ROUTES BOUNDARIES LAYER IS A polygon feature class created for the Miami-Dade Department of Solid Waste Management (DSWM). It contains the...

DRIVERS OF LONG-TERM CONVERGENCE. FOCUS ON ROMANIA

Directory of Open Access Journals (Sweden)

MANUELA UNGURU

2014-11-01

Full Text Available With initial low levels of income per capita, a declining population and relatively modest economic growth rates, there are little prospects of diminishing the gap between Romania and the EU countries. Nevertheless, in the long term, convergence is expected. The question then arises, “What are the drivers and their likely potential to boost economic growth and the catching-up process?”. This paper presents shortly the theoretical background of economic convergence and then focuses on the assessment of possible paths of Romania’s convergence towards the EU. Based on the existing long-term macroeconomic projections and the assessment of the possible future developments of the drivers of economic growth, we have built three scenarios of economic convergence, highlighting the possible timespan of convergence. We have employed growth accounting methods to decompose output growth rate into production factors’ contributions (capital and labour and total factor productivity.

Porcelain tiles by the dry route

International Nuclear Information System (INIS)

Melchiades, F. G.; Daros, M. T.; Boschi, A. O.

2010-01-01

In Brazil, the second largest tile producer of the world, at present, 70% of the tiles are produced by the dry route. One of the main reasons that lead to this development is the fact that the dry route uses approximately 30% less thermal energy them the traditional wet route. The increasing world concern with the environment and the recognition of the central role played by the water also has pointed towards privileging dry processes. In this context the objective of the present work is to study the feasibility of producing high quality porcelain tiles by the dry route. A brief comparison of the dry and wet route, in standard conditions industrially used today to produce tiles that are not porcelain tiles, shows that there are two major differences: the particle sizes obtained by the wet route are usually considerably finer and the capability of mixing the different minerals, the intimacy of the mixture, is also usually better in the wet route. The present work studied the relative importance of these differences and looked for raw materials and operational conditions that would result in better performance and glazed porcelain tiles of good quality. (Author) 7 refs.

VANET Routing Protocols: Pros and Cons

OpenAIRE

Paul, Bijan; Ibrahim, Md.; Bikas, Md. Abu Naser

2012-01-01

VANET (Vehicular Ad-hoc Network) is a new technology which has taken enormous attention in the recent years. Due to rapid topology changing and frequent disconnection makes it difficult to design an efficient routing protocol for routing data among vehicles, called V2V or vehicle to vehicle communication and vehicle to road side infrastructure, called V2I. The existing routing protocols for VANET are not efficient to meet every traffic scenarios. Thus design of an efficient routing protocol h...

Effect of exposure routes on the relationships of lethal toxicity to rats from oral, intravenous, intraperitoneal and intramuscular routes.

Science.gov (United States)

Ning, Zhong H; Long, Shuang; Zhou, Yuan Y; Peng, Zi Y; Sun, Yi N; Chen, Si W; Su, Li M; Zhao, Yuan H

2015-11-01

The lethal toxicity values (log 1/LD(50)) of 527 aliphatic and aromatic compounds in oral, intravenous, intramuscular and intraperitoneal routes were used to investigate the relationships of log 1/LD(50) from different exposure routes. Regression analysis shows that the log 1/LD(50) values are well correlated between intravenous and intraperitoneal or intramuscular injections. However, the correlations between oral and intravenous or intraperitoneal routes are relatively poor. Comparison of the average residuals indicates that intravenous injection is the most sensitive exposure route and oral administration is the least sensitive exposure route. This is attributed to the difference in kinetic process of toxicity testing. The toxic effect of a chemical can be similar or significantly different between exposure routes, depending on the absorption rates of chemicals into blood. Inclusion of hydrophobic parameter and fractions of ionic forms can improve the correlations between intravenous and intraperitoneal or oral routes, but not between intraperitoneal and oral routes. This is due to the differences of absorption rate in different exposure environments from different routes. Several factors, such as experimental uncertainty, metabolism and toxic kinetics, can affect the correlations between intravenous and intraperitoneal or oral routes. Copyright © 2015 Elsevier Inc. All rights reserved.

Frequency response functions for nonlinear convergent systems

NARCIS (Netherlands)

Pavlov, A.V.; Wouw, van de N.; Nijmeijer, H.

2007-01-01

Convergent systems constitute a practically important class of nonlinear systems that extends the class of asymptotically stable linear time-invariant systems. In this note, we extend frequency response functions defined for linear systems to nonlinear convergent systems. Such nonlinear frequency