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Dispersal of aquatic organisms by birds has long been assumed to be an important process, but quantitative studies of its frequency are scarce. We determined the presence of plant and invertebrate propagules adhering to the plumag...
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Dispersal of aquatic organisms by birds has long been assumed to be an important process, but quantitative studies of its frequency are scarce. We determined the presence of plant and invertebrate propagules adhering to the plumage or feet of 47 waterbirds of 6 species (2 ducks, 2 waders and 2 rallids) trapped during the spring migration period in two localities in Donana, south-west Spain. The percentage of waterbirds transporting propagules was high, with large differences between sites in the proportion of individuals carrying propagules (35 % and 100 %, respectively) and the numbers and types of propagules carried. Seeds of at least 15 plant species, eggs of at least 6 invertebrate species and at least one alga were encountered, with each bird carrying up to 12. different types. Seeds tended to be attached to the plumage, and invertebrate eggs to the feet. The efficiency of protocols for removing propagules from birds varied between bird and propagule species. External transport of propagules by waterbirds seems a frequent process at least at a local scale and is likely to facilitate the rapid colonisation of new or temporary wetlands, and maintain gene flow between populations. [References: 20]
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In order to extend the business viability of carbon nanotubes (CNTs), research on CNT dispersion in a solvent as well as in polymer matrix should be established. Herein, three kinds of dispersing agents, sodium deoxycholate (DOC),...
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In order to extend the business viability of carbon nanotubes (CNTs), research on CNT dispersion in a solvent as well as in polymer matrix should be established. Herein, three kinds of dispersing agents, sodium deoxycholate (DOC), sodium dodecylbenzene sulfonate (NaDDBS), polyvinyl pyrrolidone (PVP), are selected and applied to quantify the dispersibility and dispersion stability of CNT aqueous dispersion. The dispersibility of CNT dispersion with the PVP, evaluated via viscosity and particle size analyses, are superior to those with the DOC and NaDDBS dispersing agents. CNT aqueous solution dispersed with PVP showed slightly higher viscosity and narrower particle size distribution than those with DOC and NaDDBS dispersing agents. In addition, the dispersion stability of CNT dispersion with the PVP, measured via lumisizer analyses, are superior to those with the DOC and NaDDBS dispersing agents. HR-TEM analysis verifies that the outstanding dispersibility and dispersion stability of CNTs in aqueous solution are due to the effect of the robust polymer wrapping of the PVP dispersing agent on the CNT surface. From the results of this study, the guidelines for the selection of the suitable dispersing agents and the systematic evaluation of dispersibility and dispersion stability of CNT dispersions can be suggested.
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Terrestrial plants seeds, spores and pollen are often dispersed by wind. Likewise, most eggs and larvae of marine organisms are dispersed by oceanic currents. It was historically believed that the spatial scale at which dispersal ...
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Terrestrial plants seeds, spores and pollen are often dispersed by wind. Likewise, most eggs and larvae of marine organisms are dispersed by oceanic currents. It was historically believed that the spatial scale at which dispersal occurs was orders of magnitude smaller for plants than for fish. However, recent empirical estimates of seed and larval dispersal suggest that these dispersal scales are more alike than previously thought. The modeling approaches used to simulate aerial and aquatic dispersal are also converging. Similar biophysical models are developed, in which outputs of Eulerian models simulating the main physical forcing mechanism (wind or currents) are used as inputs to Lagrangian models that include biological components (such as seed terminal velocity or larval vertical migration). These biophysical models are then used to simulate trajectories of the biological entities (seeds, larvae) in three dimensions. We reflect on these converging trends by first putting them into an historical perspective, and then by comparing the physical and biological processes represented in marine larva vs. terrestrial seed dispersal models, the data used for the models output corroboration, and the tools available to perform simulations. We conclude that this convergence offers the opportunity to bridge the gap between two scientific communities which are currently largely disconnected. More broadly, we also see our comparison across systems as a useful way to strengthen the links between aquatic and terrestrial ecology by sharing knowledge, methods, tools, and concepts.
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In this work, a novel dispersant was prepared using the dichlorotriazine azo moiety (DCT) of 1-amino-4-[3-(4,6-dichlorotriazin-2-ylamino)-4-sulfophenylamino] anthraquinone-2-sulfonic acid (C. I. Reactive Blue 4) and Dodecan-1-ol (...
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In this work, a novel dispersant was prepared using the dichlorotriazine azo moiety (DCT) of 1-amino-4-[3-(4,6-dichlorotriazin-2-ylamino)-4-sulfophenylamino] anthraquinone-2-sulfonic acid (C. I. Reactive Blue 4) and Dodecan-1-ol (DDL) via a nucleophilic substitution reaction. The prepared dispersant was characterized by FTIR and H-1-NMR. The properties and dispersing ability of the novel dispersant was further investigated. The prepared dispersant was employed as novel dispersants for pigment dispersion in solvent-based printing ink application. The mechanical and optical properties of prepared dispersion were studied. The novel dispersant showed good optical and mechanical properties and possessed excellent dispersing ability for C.I. Pigment Blue 15:3, with good centrifuge and storage stability.
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Surfzone dispersion is characterized with single-particle Lagrangian statistics ofGPS-tracked drifters deployed on 5 days at Huntington Beach, California. Incident waveheights varied weakly between days, and stationary rip current...
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Surfzone dispersion is characterized with single-particle Lagrangian statistics ofGPS-tracked drifters deployed on 5 days at Huntington Beach, California. Incident waveheights varied weakly between days, and stationary rip currents did not occur. Generally,the time-dependent bulk surfzone cross-shore diffusivity tc was similar on all days,reaching a local maxima of approximately 1.5 m2 s-1 between 160 and 310 s, beforedecreasing to about 1 m2 s-1 at 1000 s. The alongshore diffusivity Kyy increasedmonotonically to 1000 s and was variable between the 5 days. For times greater than 30 s,the alongshore diffusivity is greater than the cross-shore diffusivity, consistent withprevious observations. The observed diffusivities are fit to analytic functional forms,from which asymptotic diffusivities and Lagrangian timescales are determined. Theasymptotic alongshore diffusivity R33`3), varies between 4 and 19 m2 s-1, and this variation isrelated to the variation in the maximum of the mean alongshore current i),n, broadlyconsistent with a shear dispersion scaling kiCy°1,2m. Cross-shore variation in dispersionprocesses, lumped together in the bulk it,is apparent in the non-Gaussian probabilitydistribution function of drifter displacements at intermediate times (30 s). Both biasedand unbiased diffusivity sampling errors depend on the number and length of driftertrajectories and limit aspects of the analysis.
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A major cause of seismic attenuation in fluid-saturated rocks is the flow of the pore fluid induced by the passing wave. At sonic and ultrasonic frequencies, attenuation ap-pears to be dominated by the local (pore-scale) flow betw...
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A major cause of seismic attenuation in fluid-saturated rocks is the flow of the pore fluid induced by the passing wave. At sonic and ultrasonic frequencies, attenuation ap-pears to be dominated by the local (pore-scale) flow between pores of different shapes and orientations. A simple squirt now model is developed in which all of the parameters can be independently measured or estimated from measurements. The pore space of the rock is assumed to consist of stiff poros-ity and compliant (or soft) pores present at grain contacts. The effect of isotropically distributed compliant pores is modeled by considering pressure relaxation in a disk-shaped gap between adjacent grains. This derivation gives the com-plex and frequency-dependent effective bulk and shear mod-uli of a rock, in which the compliant pores are liquid saturated and stiff pores are dry. The resulting squirt model is consis-tent with Gassmann's and Mavko–Jizba equations at low and high frequencies, respectively. The magnitude of attenuation and dispersion given by the model is directly related to the variation of dry bulk modulus with pressure and is relatively independent of fluid properties.
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In the quest of ensuring successful pigment dispersion, additives are used to aid dispersion and stabilization of pigment particles through attraction forces of various chemical nature including van der waals and liquid bridge for...
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In the quest of ensuring successful pigment dispersion, additives are used to aid dispersion and stabilization of pigment particles through attraction forces of various chemical nature including van der waals and liquid bridge forces as well as anchor groups with high affinity for pigment surface. On the other hand, dispersion efficiency is significantly dependent on the effectiveness of various dispersion equipment and their energy transfer, dispersion force and effectiveness. The common denominator for all this equipment are that; dispersion is achieved by shearing forces produced by the application of high positive and negative attrition. This article reviews and explores the nature and the significance of the various methods and forces in pigment dispersion and the various stabilization mechanisms adopted in producing stably fine pigment particles, dispersion application as well as future prospects.
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We characterize and employ a light transmission technique to measure the dispersivity of a solute in the flow of a neutrally-buoyant non-Brownian spherical particle suspension in a Hele-Shaw cell (parallelplate axial flow). Partic...
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We characterize and employ a light transmission technique to measure the dispersivity of a solute in the flow of a neutrally-buoyant non-Brownian spherical particle suspension in a Hele-Shaw cell (parallelplate axial flow). Particle radii (a) were 20 and 40 μm, the particle bulk volume fraction φ_(bulk) was 0.2, and the cell aperture was 420 ± 10 μm. In each displacement experiment a suspension with a colouring solute displaces a transparent one at constant flow rates ranging from 0.721 to 0.928 mL/min (corresponding to solute Péclet numbers (Pe_s) between 350 and 450). A reference measurement, identical to the displacement ones but without particles in the flow (φ_(bulk) = 0), were performed in the same experimental assembly for comparison purposes. A light calibration related the transmitted intensity I to the solute concentration c for each combination of φ_(bulk) and a. The time variation of the solute concentration was found to be well-fitted by the solution of the advection-dispersion equation (ADE) in the range of Pe_s studied, and consequently a dispersion coefficient D and a dispersivity l_d of the solute were measured.
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We investigate the formation and dynamics of spatially broad Dirac light bullets in nonlinear binary waveguide arrays. We show that a Dirac light bullet can be formed during propagation when a pulse with an initial profile slightl...
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We investigate the formation and dynamics of spatially broad Dirac light bullets in nonlinear binary waveguide arrays. We show that a Dirac light bullet can be formed during propagation when a pulse with an initial profile slightly different from the one of the Dirac light bullet is launched into the system. We also reveal that these Dirac light bullets are metastable and can propagate without significant distortion for hundreds of dispersion lengths even in the presence of the Raman effect, group velocity mismatch, and group velocity dispersion difference between adjacent waveguides.
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Sex-biased dispersal is common in group-living animals. Due to differences in local demographic and environmental factors, sex-biased dispersal presents many irregular patterns. In this study, a habituated, individually identified...
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Sex-biased dispersal is common in group-living animals. Due to differences in local demographic and environmental factors, sex-biased dispersal presents many irregular patterns. In this study, a habituated, individually identified Yunnan snub-nosed monkey Rhinopithecus bieti group was observed over 9?years; 192 dispersal events, including 97 male dispersal events (25 natal dispersal and 72 secondary dispersal) and 95 female dispersal events (34 natal dispersal and 61 secondary dispersal) were observed. Males and females showed different dispersal paths, dispersal ages, and dispersal patterns. Females had 2 dispersal paths, whereas males had 4 paths. In terms of age of dispersal, the male age of natal dispersal was younger than for females. Males prefer single dispersal, whereas females prefer parallel dispersal. Our study indicates that the dispersal pattern of R. bieti should be classified as a bisexual dispersal pattern. The differences in dispersal path, average age at dispersal, and dispersal path pattern indicate that Yunnan snub-nosed monkeys may still retain a loose matrilineal social system.
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