scholarly journals Satellite patches, patch expansion, and doubling time as decision metrics for invasion control:Pennisetum ciliareexpansion in southwestern Arizona

2019 ◽  
Vol 12 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Jaron D. Weston ◽  
Mitchel P. McClaran ◽  
Richard K. Whittle ◽  
Christian W. Black ◽  
Jeffrey S. Fehmi
Keyword(s):  
Control Strategy ◽  
Doubling Time ◽  
Nearest Neighbor ◽  
Average Distance ◽  
Perennial Grass ◽  
Expansion Rate ◽  
Dispersion Pattern ◽  
Invasion Speed ◽  
Pennisetum Ciliare ◽  
Efficient Control

AbstractEssential variables to consider for an efficient control strategy for invasive plants include dispersion pattern (i.e., satellite or invasion front) and patch expansion rate. These variables were demonstrated for buffelgrass [Pennisetum ciliare(L.) Link], a C4perennial grass introduced from Africa, which has invaded broadly around the world. The study site was along a roadway in southern Arizona (USA). TheP. ciliareplant distributions show the pattern of clumping associated with the satellite (nascent foci) colonization pattern (average nearest neighbor test,z-score −47.2, P<0.01). The distance between patches ranged from 0.743 to 12.8 km, with an average distance between patches of 5.6 km. Median patch expansion rate was 271% over the 3-yr monitoring period versus 136% found in other studies of establishedP. ciliarepatches. TargetingP. ciliaresatellite patches as a control strategy may exponentially reduce the areal doubling time, while targeting the largest patches may have less effect on the invasion speed.

scholarly journals Display Behavior and Spatial Distribution of the Red-Headed Manakin in the Atlantic Forest of Brazil

The Condor ◽  
2004 ◽  
Vol 106 (2) ◽  
pp. 320-335 ◽  
Author(s):  
Ivandy N. Castro-Astor ◽  
Maria Alice S. Alves ◽  
Roberto B. Cavalcanti
Keyword(s):  
Spatial Distribution ◽  
Atlantic Forest ◽  
Rio De Janeiro ◽  
Nearest Neighbor ◽  
Average Distance ◽  
The Other ◽  
Dispersion Pattern ◽  
Mata Atlântica ◽  
Display Behavior ◽  
Mata Atlantica

AbstractWe studied the display behavior and spatial distribution of the Red-headed Manakin (Pipra rubrocapilla, Pipridae) in the Atlantic Forest of the state of Rio de Janeiro, Brazil. The average distance between display sites was 72.5 ± 34.1 m (n = 11, range = 34.0–157.0 m). The study area included one 13-site lek and two solitary display sites. All sites of the same lek were within earshot of at least one other site. Males occupied the same display sites between years. The dispersion pattern of males is typical of exploded or dispersed leks. Males were more likely to interact with their nearest neighbor than with males from more distant display sites. Red-headed Manakin lekking behavior is remarkably complex, including 11 display elements, two of them not found in other members of the P. erythrocephala clade, nine vocalizations, and one mechanical sound previously undescribed in the Red-headed Manakin. The males performed both solitary displays and coordinated displays with other males on both their own display sites and on those of the other males. Most of the time, two definitive-plumaged males displayed together. The displays, vocalizations, and mechanical sound recorded in this study contribute to our understanding of the evolution of display behavior in manakins, mainly to the members of the P. erythrocephala clade.Despliegue de Cortejo y Distribución Espacial de Pipra rubrocapilla en la Mata Atlántica de BrasilResumen. Estudiamos el despliegue de cortejo y la distribución espacial de Pipra rubrocapilla (Pipridae) en el área de la Mata Atlántica del Estado de Río de Janeiro, Brasil. La distancia promedio entre los lugares de cortejo fue de 72.5 ± 34.1 m (n = 11, rango = 34.0–157.0). El área de estudio incluyó un lek con 13 lugares de cortejo y dos lugares de cortejo aislados. Desde un lugar de cortejo en un lek se podía oir la vocalización del vecino más próximo. Los machos ocuparon los mismos lugares de cortejo durante años, y presentaron la distribución espacial típica de los leks dispersos. Observamos más interacciones entre los machos de los lugares de cortejo más próximos. El despliegue de cortejo de P. rubrocapilla es muy complejo, incluyendo 11 elementos de cortejo (dos de ellos no descritos para otras especies del clado P. erythrocephala), nueve vocalizaciones y un sonido mecá nico, que hasta el momento, no había sido registrado para P. rubrocapilla. Los machos ejecutan despliegues de cortejo solitarios y despligues coordinados con otros machos en sus lugares de cortejo y en los de otros machos. La mayoría de las veces, el despliegue de cortejo es praticado por dos machos adultos. El despliegue de cortejo, las vocalizaciones y el sonido mecánico registrados en este estudio contribuyen al entendimiento de la evolución del despliegue de cortejo en los pípridos, principalmente en las especies que conforman el clado de P. erythrocephala.

Temporal Changes in Habitat Selection and Nest Spacing in a Colony of Ross' and Lesser Snow Geese

The Auk ◽  
1983 ◽  
Vol 100 (2) ◽  
pp. 335-343 ◽  
Author(s):  
M. Robert McLandress
Keyword(s):  
Nearest Neighbor ◽  
Average Distance ◽  
Habitat Preferences ◽  
Nearest Neighbors ◽  
Nest Density ◽  
Snow Goose ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Average Size ◽  
Island Habitats

Abstract I studied the nesting colony of Ross' Geese (Chen rossii) and Lesser Snow Geese (C. caerulescens caerulescens) at Karrak Lake in the central Arctic of Canada in the summer of 1976. Related studies indicated that this colony had grown from 18,000 birds in 1966-1968 to 54,500 birds in 1976. In 1976, geese nested on islands that were used in the late 1960's and on an island and mainland sites that were previously unoccupied. Average nest density in 1976 was three-fold greater than in the late 1960's. Consequently, the average distance to nearest neighbors of Ross' Geese in 1976 was half the average distance determined 10 yr earlier. The mean clutch size of Ross' Geese was greater in island habitats where nest densities were high than in less populated island or mainland habitats. The average size of Snow Goose clutches did not differ significantly among island habitats but was larger at island than at mainland sites. Large clutches were most likely attributable to older and/or earlier nesting females. Habitat preferences apparently differed between species. Small clutches presumably indicated that young geese nested in areas where nest densities were low. The establishment of mainland nesting at Karrak Lake probably began with young Snow Geese using peripheral areas of the colony. Young Ross' Geese nested in sparsely populated habitats on islands to a greater extent than did Snow Geese. Ross' Geese also nested on the mainland but in lower densities than Ross' Geese nesting in similar island habitats. Successful nests with the larger clutches had closer conspecific neighbors than did successful nests with smaller clutches. The species composition of nearest neighbors changed significantly with distance from Snow Goose nests but not Ross' Goose nests. Nesting success was not affected by the species of nearest neighbor, however. Because they have complementary antipredator adaptations, Ross' and Snow geese may benefit by nesting together.

LATTICE DYNAMICS OF THE BINARY APERIODIC CHAINS OF ATOMS I: FRACTAL DIMENSION OF PHONON SPECTRA

1995 ◽  
Vol 09 (12) ◽  
pp. 1429-1451 ◽  
Author(s):  
WŁODZIMIERZ SALEJDA
Keyword(s):  
Fractal Dimension ◽  
Lattice Dynamics ◽  
Nearest Neighbor ◽  
Average Distance ◽  
Local Maximum ◽  
Fractal Dimensions ◽  
Dimension Formula ◽  
Phonon Spectra ◽  
Wide Range ◽  
Silver Mean

The microscopic harmonic model of lattice dynamics of the binary chains of atoms is formulated and studied numerically. The dependence of spring constants of the nearest-neighbor (NN) interactions on the average distance between atoms are taken into account. The covering fractal dimensions [Formula: see text] of the Cantor-set-like phonon spec-tra (PS) of generalized Fibonacci and non-Fibonaccian aperiodic chains containing of 16384≤N≤33461 atoms are determined numerically. The dependence of [Formula: see text] on the strength Q of NN interactions and on R=mH/mL, where mH and mL denotes the mass of heavy and light atoms, respectively, are calculated for a wide range of Q and R. In particular we found: (1) The fractal dimension [Formula: see text] of the PS for the so-called goldenmean, silver-mean, bronze-mean, dodecagonal and Severin chain shows a local maximum at increasing magnitude of Q and R>1; (2) At sufficiently large Q we observe power-like diminishing of [Formula: see text] i.e. [Formula: see text], where α=−0.14±0.02 and α=−0.10±0.02 for the above specified chains and so-called octagonal, copper-mean, nickel-mean, Thue-Morse, Rudin-Shapiro chain, respectively.

scholarly journals Research on Control Method of Microgrid Based on Multi Distributed Generation

2021 ◽  
Vol 2083 (2) ◽  
pp. 022099
Author(s):  
Chengyi Yue ◽  
Binbin Bei
Keyword(s):  
Distributed Generation ◽  
Control Strategy ◽  
Power Supply ◽  
Control Method ◽  
Peer To Peer ◽  
Strategy Method ◽  
Distributed Power ◽  
Simulink Simulation ◽  
Efficient Control ◽  
Peer Control

Abstract Reducing the dependence of microgrid upon the communication system and realizing the efficient control of multiple distributed generation of the microgrid are problems that need to be solved urgently. Through the research, based on multiple microgrid operation modes, the peer-to-peer control strategy in microgrid is investigated, and the peer-to-peer control strategy method of microgrid is given for a variety of complex control problems of distributed power According to the peer-to-peer control strategy method, distributed power supply adopts droop control in adjusting distributed power supply in output voltage and frequency; the droop controller has P-f and Q-U droop characteristics. This paper establishes a peer-to-peer control microgrid simulation model, adopts the droop controller designed in this paper to island mode and grid-connected mode, and investigates how the microgrid switches between the two modes. In accordance with Matlab/Simulink simulation outcomes, the research examines frequency, voltage and power changes in distributed generation in the microgrid, and verifies the validity and feasibility of microgrid peer-to-peer control strategy.

The spatial pattern of a Juniperus communis var. depressa population on a continental dune in subarctic Québec, Canada

1999 ◽  
Vol 29 (4) ◽  
pp. 446-450 ◽  
Author(s):  
Gilles Houle ◽  
Mario Duchesne
Keyword(s):  
Sex Ratio ◽  
Nearest Neighbor ◽  
Dispersion Pattern ◽  
Neighbor Distance ◽  
Juniperus Communis ◽  
Biased Sex Ratio ◽  
Males And Females ◽  
Nearest Neighbor Distance ◽  
Population Dispersion ◽  
Crown Size

We performed a nearest-neighbor analysis to determine the population dispersion pattern and the association between males and females in a Juniperus communis L. var. depressa Pursh population occupying a continental dune in subarctic Quebec, Canada. The overall dispersion pattern was contagious, and males (or females) were proportionately as likely to have a male as they were to have a female nearest neighbor. Crown size was positively related to nearest-neighbor distance for the male-male comparison only, suggesting a somewhat stronger intrasex competition between males. Nearest-neighbor distance increased with crown size (significantly related to age) suggesting a change in the intensity of aggregation with age possibly related to self-thinning. Higher mortality as a result of stronger male-male competition could explain the female-biased sex ratio and the absence of spatial segregation between sexes. The overall contagious dispersion pattern in the population may be related to the fact that most seed cones fall directly underneath the mother plant. Birds can eat the cones of J. communis and thus disperse seeds. However, these seeds are deposited in clumps, a process that may also explain contagion within the population.

An Efficient Control Strategy of Epidemic Spreading on Scale-Free Networks

2009 ◽  
Vol 26 (6) ◽  
pp. 068901 ◽  
Author(s):  
Zhang Hai-Feng ◽  
Li Ke-Zan ◽  
Fu Xin-Chu ◽  
Wang Bing-Hong
Keyword(s):  
Control Strategy ◽  
Epidemic Spreading ◽  
Scale Free ◽  
Scale Free Networks ◽  
Efficient Control

Mutual Passivation in Dilute GaNxAs1-x Alloys

2005 ◽  
Vol 864 ◽  
Author(s):  
K. M. Yu ◽  
W. Walukiewicz ◽  
J. Wu ◽  
D. E. Mars ◽  
M. A. Scarpulla ◽  
...  
Keyword(s):  
Nearest Neighbor ◽  
Diffusion Length ◽  
Average Distance ◽  
Alloy System ◽  
Group Iv ◽  
Semiconductor Alloys ◽  
Drastic Reduction ◽  
Free Electron Concentration ◽  
Ternary Semiconductor ◽  
Good Agreement

AbstractThe dilute GaNxAs1-x alloys (with x up to 0.05) have exhibited many unusual properties as compared to the conventional binary and ternary semiconductor alloys. We report on a new effect in the GaNxAs1-x alloy system in which electrically active substitutional group IV donors and isoelectronic N atoms passivate each other's activity. This mutual passivation occurs in dilute GaNxAs1-x doped with group IV donors through the formation of nearest neighbor IVGa- NAs pairs when the samples are annealed under conditions such that the diffusion length of the donors is greater than or equal to the average distance between donor and N atoms. The passivation of the shallow donors and the NAs atoms is manifested in a drastic reduction in the free electron concentration and, simultaneously, an increase in the fundamental bandgap. This mutual passivation effect is demonstrated in both Si and Ge doped GaNxAs1-x alloys. Analytical calculations of the passivation process based on Ga vacancy mediated diffusion show good agreement with the experimental results.

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