ライフサイエンスコーパス: levy

1 We associate this with the Shoemaker-Levy 9 impacts of July 1994.

2 increased dramatically during the Shoemaker-Levy 9 impacts.

3 considered to be products of comet Shoemaker-Levy 9 impacts; characterization of the morphology of th

4 dances from the collision of comet Shoemaker-Levy 9 into Jupiter.

5 tion probability), whereas it goes over to a Levy alpha-stable distribution in the very large populat

6 Clark & Levy (American Naturalist, 131, 1988, 271-290) described

7 ted, and significantly diverge from both the Levy and Brownian models identified in predators searchi

8 sh), with some individuals switching between Levy and Brownian movement as they traversed different h

9 captures, to show that both species exhibit Levy and Brownian movement patterns.

10 ical methods that have been used to identify Levy behaviour has recently been questioned.

11 d in vertebrates to test for the presence of Levy behaviour patterns in the absence of complex prey d

12 ce of these two principal patterns and found Levy behaviour to be associated with less productive wat

13 lting in unusually strong selective pressure levied by their host ants.

14 Clark & Levy described an antipredation window for smaller plank

15 ntings are fractals produced by the artist's Levy distributed motion and that fractal analysis may be

16 argets in a 2D space with steps drawn from a Levy distribution with the exponent varying from [Formul

17 ions of these Fibonacci modes are asymmetric Levy distributions that are completely fixed by the macr

18 bility models for mosquito behavior, such as Levy distributions.

19 Levy et al. and Nowarski et al. reveal how microbiota-de

20 In this issue, a pair of studies (Levy et al. and Sanders et al.) identify several de novo

21 Levy et al. have sequenced the complete genome of a huma

22 like partial CO2 rebreathing was studied by Levy et al., who suggested that this method may be used

23 While Levy features do exist, locusts' movement patterns are m

24 When Steward and Levy first reported their observation of polyribosomes a

25 movement for other organisms, and to propose Levy flight analysis as a potential real-time ecosystem

26 dom trajectories predicted by the prevailing Levy flight and random walk models, human trajectories s

27 ly long flights, essential for demonstrating Levy flight behaviour, were spurious.

28 albatross flights, and find no evidence for Levy flight behaviour.

29 tals, we find the same prevalence of optimal Levy flight characteristics (mu approximately 2) in both

30 ity has been empirically observed to exhibit Levy flight characteristics and behaviour with power-law

31 ctions form part of what has been termed the Levy flight foraging hypothesis (LFF) which states that

32 rehensive support for the predictions of the Levy flight foraging hypothesis and in particular for th

33 d support to the possibility that biological Levy flight may have naturally evolved as a search strat

34 ribution of flight lengths, corresponding to Levy flight motion, is an optimal strategy.

35 phical approach has been adopted to conclude Levy flight movement for other organisms, and to propose

36 ge about resources' locations is incomplete, Levy flight movements optimize the success of random sea

37 tern is a specialised random walk known as a Levy flight, whereas when prey is abundant, simple Brown

38 An optimal search theory, the so-called Levy-flight foraging hypothesis, predicts that predators

39 These results are consistent with the Levy-flight foraging hypothesis, supporting the contenti

40 ed by optimal Levy walks and shows that the 'Levy-flight foraging' hypothesis has a broad hinterland.

41 he adoption of an optimal biased scale-free (Levy-flight) searching strategy.

42 movement patterns approximated by truncated Levy flights and Brownian behaviour were present in the

43 wer-law distributed tails, characteristic of Levy flights and Levy walks.

44 rithmic binning methods were consistent with Levy flights and rank-frequency methods-comparing altern

45 Levy flights are random walks, the step lengths of which

46 Levy flights are scale-free (fractal) search patterns fo

47 riven by multiplicative noises and incumbent Levy flights arise naturally in the modelling of swarms.

48 We hereby provide a new window on Levy flights as models of movement pattern data, linking

49 Levy flights display fractal properties, have no typical

50 ciency of a minimalist search model based on Levy flights in the absence and presence of an external

51 Consequently, whether foragers exhibit Levy flights in the wild remains unclear.

52 searches, movements approximated by optimal Levy flights may have naturally evolved in organisms to

53 tterns during foraging, and demonstrate that Levy flights of predators in dynamic natural environment

54 raging hypothesis (LFF) which states that as Levy flights optimise random searches, movements approxi

55 Although Levy flights turn out to be efficient search processes w

56 ), whereas movements approximating truncated Levy flights were present when searching for sparsely di

57 evidence that wandering albatrosses perform Levy flights when searching for prey on the ocean surfac

58 tors should adopt search strategies known as Levy flights where prey is sparse and distributed unpred

59 Contrary to claims that Levy flights with a critical exponent alpha = 1 are opti

60 dered optimal; in particular, more ballistic Levy flights with exponent [Formula: see text] are gener

61 area-restricted search, perform better than Levy flights yet can still generate heavy-tailed distrib

62 free, Levy stable jump length distributions (Levy flights) optimize the search for sparse targets.

63 r bounded power-law distributions (truncated Levy flights).

64 The inclusion of such noises gives rise to Levy flights, a popular but controversial model of scale

65 sets, finding that none exhibits evidence of Levy flights, and that the original graphical approach i

66 prominently in the literature on biological Levy flights, being seen, perhaps, as no more than a mat

67 gth of the empirical evidence for biological Levy flights.

68 ion into the 'feast and famine' effect, with Levy foragers in heterogeneous environments experiencing

69 However, the putative success of Levy foraging has been demonstrated only in model simula

70 Therefore overall, optimal Levy foraging results in more predictable resources in u

71 Germ-line transformation using the levy(+) gene rescued the mutant flies from all phenotype

72 to the UK Government's soft drinks industry levy have been seen, but the government cannot continue

73 imulations we show that the incorporation of Levy intermittence in an otherwise nonintermittent searc

74 We propose that Levy intermittence may come from reorientation mechanism

75 The health impact of the soft drinks levy is dependent on its implementation by industry.

76 TATION: The health impact of the soft drinks levy is dependent on its implementation by industry.

77 on, with additional benefits possible if the levy is passed on to purchasers through raising of the p

78 nd the tail of NA distributions fit a stable Levy law with exponents that remained invariant over the

79 The findings suggest that Levy-like behavior has been used by foragers since at le

80 This may explain why Levy-like behaviour seems to be widespread among diverse

81 Prey density distributions also display Levy-like fractal patterns, suggesting response movement

82 ched and dispersed conditions led to similar Levy-like movement distributions.

83 ind the first evidence, to our knowledge, of Levy-like search strategies in extinct animals.

84 ord may have triggered adaptation of optimal Levy-like searches.

85 t come closest to approximating advantageous Levy looping searches.

86 After checking various function types, the Levy-Martin function proved to be most suitable for this

87 n the basis of this function, we defined the Levy-Martin parameter and suggest using this parameter f

88 The Levy motion activates a transition from the low concentr

89 er noise intensities and larger jumps of the Levy motion shortens the MFET and thus benefits transiti

90 characteristics are easily generated without Levy motion, both by freehand drawing and gaussian rando

91 modeled by Brownian motion and alpha-stable Levy motion.

92 ses captured by wandering albatrosses during Levy movements exceed daily energy requirements by nearl

93 The levy mutants provide a genetic model to understand the m

94 The data from levy mutants reveal a COX-mediated pathway in Drosophila

95 rst passage times show complex effects under Levy noise, especially the stability index and skewness

96 s from one protein imposed by a non-Gaussian Levy noise, which is able to describe even large jumps,

97 that a large burst of one protein due to the Levy noises can induce coherent switches even with small

98 also imply that the presence of non-Gaussian Levy noises has fundamentally changed the escape mechani

99 enger are often greater than airport charges levied on airlines for infrastructure use.

100 First, we consider a tax to be levied on tobacco advertising and promotion or, as an al

101 effect of possible industry responses to the levy on obesity, diabetes, and dental caries.

102 h, 2016, the UK Government proposed a tiered levy on sugar-sweetened beverages (SSBs; high tax for dr

103 ajority of ratios, DeltaX(i) scales with the Levy parameter alpha approximately 1, even though only a

104 n the notion that albatrosses do not exhibit Levy patterns during foraging, and demonstrate that Levy

105 e use maximum-likelihood methods to test for Levy patterns in relation to environmental gradients in

106 However, it is possible that the observed Levy patterns of white sharks may not arise from an adap

107 lved in such a way that they exploit optimal Levy patterns.

108 wnian walk clusters that converge to optimal Levy patterns.

109 an Z score, we find that P(DeltaZ) follows a Levy PDF with power-law exponent alpha approximately 1,

110 We find that an asymmetric Levy PDF, L, characterized by infinite variance, models

111 We thus find that Levy PDFs describe both the static and dynamics of credi

112 on system, we include symmetric alpha-stable Levy perturbations.

113 sions were seen with both the CMT and Roussy-Levy phenotypes, in seven patients.

114 60s Mandelbrot and Fama proposed a symmetric Levy probability distribution function (PDF) to describe

115 A Levy process does not consider when or where resources a

116 of movement in each time interval, (iii) are Levy processes in which distance or waiting-time (time-b

117 ions do not accurately reflect human search, Levy processes may still describe movement in dispersed

118 the proposal that many animals forage using Levy processes nonetheless remains.

119 d a maximum-likelihood framework for fitting Levy processes to comparative morphological data.

120 However, Levy processes too have come into question based on the

121 weak chaos leads to superdiffusive behavior (Levy processes with drift).

122 theoretical contributions have posited that "Levy random walks"-which can produce power law path leng

123 Steward and Levy's discovery, however, raised the intriguing possibi

124 desert ant Melophorus bagoti approximates a Levy search pattern by using an intrinsic bi-exponential

125 insic bi-exponential walk and does so when a Levy search pattern is advantageous.

126 Strong support was found for Levy search patterns across 14 species of open-ocean pre

127 s of these surprising insights, arguing that Levy search patterns are an emergent property of fundame

128 bagoti are found to approximate advantageous Levy search patterns.

129 a power-law distribution, the hallmark of a Levy search.

130 This predicts that optimal Levy searches may emerge from simple behaviors observed

131 random search processes based on scale-free, Levy stable jump length distributions (Levy flights) opt

132 on processes, the fractal renewal process, a Levy-stable process, a fractional-difference process, an

133 d dark periods ('on' and 'off' times) follow Levy statistics.

134 s analyzed as a fluctuation according to the Levy statistics.

135 Thus, CD8+ T-cell behaviour is similar to Levy strategies reported in organisms ranging from musse

136 ght could be classified as having the Roussy-Levy syndrome.

137 re we report mutations in a gene (designated levy) that codes for subunit VIa of cytochrome c oxidase

138 rs have higher encounter rates when adopting Levy-type foraging in natural-like prey fields compared

139 arse and heterogeneous environments: (i) the Levy walk and (ii) the composite correlated random walk

140 ll motility in tissues resembles a random or Levy walk and is regulated in part by external factors i

141 Here we evaluate Brownian motion, Levy walk and several correlated random walks (CRWs) aga

142 In this paper, we propose to explain the Levy walk behaviour observed in human mobility patterns

143 oti which suggest that animals approximate a Levy walk by adopting an intrinsic composite movement st

144 at correlated random walks are a part of the Levy walk family.

145 ent models such as correlated random walk or Levy walk for assessing optimum path types.

146 al methods would have found evidence for the Levy walk for some individuals, a comparison of the Levy

147 Levy walk is competitive in capturing some aspects of ne

148 er support for the evolutionary advantage of Levy walk movement patterns is provided by an investigat

149 This result provides new insights into the Levy walk movement patterns of some destructive foragers

150 ate concerning the theoretical generality of Levy walk optimisation.

151 providing an explanation to the emergence of Levy Walk patterns that characterize human mobility patt

152 n/reaction scales can explain to some extent Levy walk searching patterns of predators at larger scal

153 lk for some individuals, a comparison of the Levy walk to CCRWs showed stronger support for the latte

154 The mussels realise this Levy walk to good approximation across a biologically me

155 extended indefinitely would correspond to a Levy walk whose characteristic (power-law) exponent is t

156 andom search for sparse resources known as a Levy walk, but little is known of the origins and evolut

157 fusive, scale-free movement pattern called a Levy walk, which is considered optimal when foraging for

158 de Jager et al. concluded that mussels Levy walk.

159 the brain is well described by a generalized Levy walk.

160 er than one-behaviour strategies such as the Levy walk.

161 ws another random process known as truncated Levy walk.

162 ith these data and found that mussels do not Levy walk: Their movement is best described by a composi

163 ony fishes, sea turtles and penguins-exhibit Levy-walk-like behaviour close to a theoretical optimum.

164 It follows from this that vast numbers of Levy walkers could be hiding in plain sight.

165 be those that come closest to being optimal Levy walkers.

166 promotes the searching efficiencies of some Levy walks above that of ballistic motion.

167 Nevertheless, we show that Levy walks and ballistic movements can be equally or alm

168 been posited as a potential replacement for Levy walks and it has also been suggested that CCRWs hav

169 patterns that can be approximated by optimal Levy walks and shows that the 'Levy-flight foraging' hyp

170 We also show that Levy walks are advantageous when searching for targets t

171 Levy walks are characterized by trajectories that have s

172 Levy walks are specialized random walks giving rise to f

173 esis: namely that some organisms approximate Levy walks as an innate CCRW.

174 have been posited as a strong alternative to Levy walks as models of multi-scale forager movement pat

175 We find that both Brownian and Levy walks fail to capture the complexity of T cell moti

176 ted suggestions, although disagreement, that Levy walks have functional advantages over Brownian moti

177 evidence of super-diffusion consistent with Levy walks in bacteria suggests that this strategy may h

178 ers, the Hadza of northern Tanzania, perform Levy walks in nearly one-half of all foraging bouts.

179 ggest that complex search patterns, like the Levy walks made by mud snails, can have their mechanisti

180 Additionally, Levy walks may have become common early in our genus whe

181 Levy walks occur when searching for a wide variety of fo

182 nian-like steps self-organize into truncated Levy walks through an apparent time-independent positive

183 ection pressures, evolve to resemble optimal Levy walks when foraging is non-destructive.

184 s (i.e. straight-lines movements) outperform Levy walks when searching for targets that once located

185 the foraging and search efficiencies of 2-D Levy walks with a range of exponents, target resource di

186 el search behavior using random walks (e.g., Levy walks) that match empirical movement distributions.

187 for optimal random search patterns, known as Levy walks, in empirical movement data is mounting for a

188 Other possible strategies are random and Levy walks, which have trajectories and turn frequencies

189 esis that unites correlated random walks and Levy walks.

190 performing super-diffusion, consistent with Levy walks.

191 suggested that CCRWs have been mistaken for Levy walks.

192 ales that is consistent with the presence of Levy walks.

193 ed tails, characteristic of Levy flights and Levy walks.

194 ations reporting that many organisms perform Levy walks; movement patterns that seemingly stand apart