Anticipatory memory for regular and random patterns.

2020 ◽  
Vol 46 (9) ◽  
pp. 965-978 ◽  
Author(s):  
Irem Yildirim ◽  
Helene Intraub
Keyword(s):  
Random Patterns

Soap, cells and statistics—random patterns in two dimensions

1984 ◽  
Vol 25 (1) ◽  
pp. 59-99 ◽  
Author(s):  
D. Weaire ◽  
N. Rivier
Keyword(s):  
Two Dimensions ◽  
Random Patterns

scholarly journals Climate-induced phenological shifts in a Batesian mimicry complex

2018 ◽  
Vol 116 (3) ◽  
pp. 929-933 ◽  
Author(s):  
Christopher Hassall ◽  
Jac Billington ◽  
Thomas N. Sherratt
Keyword(s):  
Large Scale ◽  
Computer Game ◽  
Species Traits ◽  
Batesian Mimicry ◽  
Model Organisms ◽  
Fitness Costs ◽  
Symbiotic Relationships ◽  
Phenological Shifts ◽  
Phenological Synchrony ◽  
Random Patterns

Climate-induced changes in spatial and temporal occurrence of species, as well as species traits such as body size, each have the potential to decouple symbiotic relationships. Past work has focused primarily on direct interactions, particularly those between predators and prey and between plants and pollinators, but studies have rarely demonstrated significant fitness costs to the interacting, coevolving organisms. Here, we demonstrate that changing phenological synchrony in the latter part of the 20th century has different fitness outcomes for the actors within a Batesian mimicry complex, where predators learn to differentiate harmful “model” organisms (stinging Hymenoptera) from harmless “mimics” (hoverflies, Diptera: Syrphidae). We define the mimetic relationships between 2,352 pairs of stinging Hymenoptera and their Syrphidae mimics based on a large-scale citizen science project and demonstrate that there is no relationship between the phenological shifts of models and their mimics. Using computer game-based experiments, we confirm that the fitness of models, mimics, and predators differs among phenological scenarios, creating a phenologically antagonistic system. Finally, we show that climate change is increasing the proportion of mimetic interactions in which models occur first and reducing mimic-first and random patterns of occurrence, potentially leading to complex fitness costs and benefits across all three actors. Our results provide strong evidence for an overlooked example of fitness consequences from changing phenological synchrony.

scholarly journals Binocular vision profilometry for large-sized rough optical elements using binarized band-limited pseudo-random patterns

2019 ◽  
Vol 27 (8) ◽  
pp. 10890 ◽  
Author(s):  
Chao Li ◽  
Changhe Zhou ◽  
Chaofeng Miao ◽  
Yu Yan ◽  
Junjie Yu
Keyword(s):  
Binocular Vision ◽  
Optical Elements ◽  
Band Limited ◽  
Random Patterns

scholarly journals Biotechnology-Derived Chitosans with Non-Random Patterns of Acetylation Differ from Conventional Chitosans in Their Properties and Activities

2021 ◽  
Author(s):  
Jasper Wattjes ◽  
Sruthi Sreekumar ◽  
Anna Niehues ◽  
Tamara Mengoni ◽  
Ana Carina Loureiro Mendes ◽  
...  
Keyword(s):  
Biological Activities ◽  
Building Blocks ◽  
Degree Of Polymerization ◽  
Natural Process ◽  
Solution Properties ◽  
Potential Applications ◽  
Random Patterns

Chitosans are versatile biopolymers with multiple biological activities and potential applications. They are linear copolymers of glucosamine and N-acetylglucosamine defined by their degree of polymerization (DP), fraction of acetylation (<i>F<sub>A</sub></i>), and pattern of acetylation (PA). Technical chitosans produced chemically from chitin possess defined DP and FA but random PA, while enzymatically produced natural chitosans are likely to have non-random PA. This natural process has not been replicated using biotechnology because chitin de-N-acetylases do not efficiently deacetylate crystalline chitin. Here, we show that such enzymes can partially N-acetylate polyglucosamine in the presence of excess acetate, yielding chitosans with <i>F<sub>A</sub></i> up to 0.7 and an enzyme-dependent non-random PA. The biotech chitosans differ from technical chitosans both in terms of physicochemical and nanoscale solution properties and biological activities. As with synthetic block co-polymers, controlling the distribution of building blocks within the biopolymer chain will open a new dimension of chitosan research and exploitation.

scholarly journals Effects of Element Type and Spatial Grouping on Symmetry Detection

Perception ◽  
1993 ◽  
Vol 22 (5) ◽  
pp. 565-587 ◽  
Author(s):  
Paul J Locher ◽  
Johan Wagemans
Keyword(s):  
Mirror Symmetry ◽  
Symmetry Axis ◽  
Detection Accuracy ◽  
Axis Orientation ◽  
Primal Sketch ◽  
Affect Detection ◽  
Spatial Grouping ◽  
Element Type ◽  
Random Patterns ◽  
Advance Knowledge

The influence of local and global attributes of symmetric patterns on the perceptual salience of symmetry was investigated. After tachistoscopic viewing, subjects discriminated between symmetric and either random patterns (experiment 1) or their perturbed counterparts (experiment 2) created by replacing one third of the mirror element-pairs of symmetric stimuli with ‘random’ elements. In general, it was found that perceptibility of symmetry, measured by response time and detection accuracy, was not influenced in a consistent way by type of pattern element (dots or line segments oriented vertically, horizontally, obliquely, or in all three orientations about the symmetry axis). Nor did axis orientation (vertical, horizontal, oblique), advance knowledge of axis orientation, practice effects, or subject sophistication differentially affect detection. A highly salient global percept of symmetry emerged, on the other hand, when elements were clustered together within a pattern, or grouped in symmetric pairs along a single symmetry axis or two orthogonal axes. Results suggest that mirror symmetry is detected preattentively, presumably by some kind of integral code which emerges from the interaction between display elements and the way they are organized spatially. It is proposed that symmetry is coded and signalled by the same spatial grouping processes as those responsible for construction of the full primal sketch.

Composition patterns and network structure of epiphyte–host interactions in Chilean and New Zealand temperate forests

2021 ◽  
Author(s):  
A Taylor ◽  
A Saldaña ◽  
G Zotz ◽  
C Kirby ◽  
I Díaz ◽  
...  
Keyword(s):  
New Zealand ◽  
Host Species ◽  
Species Interactions ◽  
Temperate Forests ◽  
Null Model ◽  
Host Interactions ◽  
Host Trees ◽  
Specific Host ◽  
Random Patterns ◽  
Epiphyte Species

Ecological networks are becoming increasingly used as a framework to study epiphyte–host interactions. However, efforts to quantify the properties of epiphyte–host networks have produced inconsistent results. Epiphyte–host interactions in New Zealand and Chilean temperate forests were quantified to test for non-random patterns in nestedness, negative co-occurrences, number of links, and network specialisation. Results showed that three out of five New Zealand networks were significantly more nested than null model expectations, compared with just one out of four Chilean networks. Epiphytes co-occurred more often than null model expectations in one New Zealand network and one in Chile. In all cases, the number of links maintained by each epiphyte and host species was consistent with null model expectations. Lastly, two New Zealand networks and one in southern Chile were significantly less specialised than null model expectations, with all remaining networks returning low specialisation scores. As such, aside from the tendency for greater nestedness in New Zealand networks, most epiphyte species were distributed on their host trees at random. We attribute the result of nestedness in New Zealand to the abundance of large nest epiphytes (Astelia spp. in particular), which may facilitate the sequential colonisation of epiphyte species on developing host trees. The lack of negative co-occurrences suggests that negative species interactions are not an important determinant of species assemblage structure. Low network specialisation scores suggest that epiphytes are selecting for specific host traits, rather than specific host species for colonisation.

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