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The two scorpionfish species Scorpaena maderensis and S. porcus are well camouflaged ambush predators that rapidly change body colouration to adjust to background colour in less than 1 min. We tested whether individuals of both species also adjust body pattern to that of the background. We placed fish on backgrounds of different pattern granularity and quantified the change in fish body pattern over 1 min. We used calibrated image analysis to analyse the patterns from the visual perspective of a prey fish species using a granularity (pattern energy) analysis and an image clustering approach. In our experiment, fish did not change their most contrasting pattern components as defined by the dominant marking size, but changed their average marking size. Moreover, fish responded with a change in pattern in contrast to the different experimental backgrounds, especially when compared to the acclimation phase. These results indicate that scorpionfish have one main pattern that can be adjusted by modulating its internal contrast. A reduction in pattern contrast could thereby improve background matching, while an increase could promote camouflage via disruptive colouration. [ABSTRACT FROM AUTHOR]

Abstract The two scorpionfish species Scorpaena maderensis and S. porcus are well camouflaged ambush predators that rapidly change body colouration to adjust to background colour in less than 1 min. We tested whether individuals of both species also adjust body pattern to that of the background. We placed fish on backgrounds of different pattern granularity and quantified the change in fish body pattern over 1 min. We used calibrated image analysis to analyse the patterns from the visual perspective of a prey fish species using a granularity (pattern energy) analysis and an image clustering approach. In our experiment, fish did not change their most contrasting pattern components as defined by the dominant marking size, but changed their average marking size. Moreover, fish responded with a change in pattern in contrast to the different experimental backgrounds, especially when compared to the acclimation phase. These results indicate that scorpionfish have one main pattern that can be adjusted by modulating its internal contrast. A reduction in pattern contrast could thereby improve background matching, while an increase could promote camouflage via disruptive colouration.

The processing of pharmaceuticals by supercritical fluids requires the correct assessment and prediction of the solubility of solid compounds in a supercritical fluid. In this work, the solubility of two drugs, namely ibuprofen and salicylic acid, in supercritical carbon dioxide at different temperatures (308–333 K) and pressures up to 35 MPa was regressed using four different thermodynamic models: Soave–Redlich–Kwong equation of state, cubic plus association equation of state, quadrupolar cubic plus association (qCPA), and the regular solution theory tuned by the Flory–Huggins equation. Adjustable parameters of each model were regressed and reported at the studied temperatures. A comparison of the models' performances showed that CPA and qCPA models with AARD% 1.34 and 2.16 for ibuprofen and 1.63 and 1.65 for salicylic acid are superior to the other applied methods. [ABSTRACT FROM AUTHOR]

A well‐known example of visual camouflage in birds is the plumage coloration of the Eurasian Treecreeper Certhia familiaris, yet this species' camouflage has never been objectively quantified. Here, we quantify Treecreeper camouflage in its boreal forest habitat, test whether Treecreepers better match tree backgrounds at nest‐site, territory or habitat spatial scales, and explore which common tree species provide the best background match. Using photographic data of the birds and forested backgrounds, we test their background match using human, ferret and avian vision modelling. We found that a Treecreeper's wing and mantle provided the closest background matching, whereas the wing stripe and tail were more conspicuous against tree trunks. Vision modelling also suggests that Treecreeper camouflage provides a better protection against mammalian than against avian vision. The matching was not significantly different across spatial scales in local spruce forests. However, the background match was better on conifers than on deciduous trees. Our results support the long‐standing conjecture of Treecreeper camouflage but also suggest that the camouflage is an adaptation especially against mammalian predators, which are important nest predators of Treecreepers. [ABSTRACT FROM AUTHOR]

Camouflage helps animals to hide from predators and is therefore key to survival. Although widespread convergence of animal phenotypes to their natural environment is well‐established, there is a lack of knowledge about how species compromise camouflage accuracy across different background types in their habitat.Here we tested how background matching has responded to top–down selection by avian and mammalian predators using Sahara–Sahel desert rodents in North Africa.We show that the fur colouration of several species has become an accurate match to different types of desert habitats. This is supported by a correlation analysis of colour and pattern metrics, investigation of animal‐to‐background similarities at different spatial scales and is confirmed by modelling of two predator vision systems.The background match was closest across large (or global) spatial scales, suggesting a generalist camouflage tactic for many background types. Some species, may have a better match to the background over small (or focal) spatial scales, which could be the result of habitat choices or differential predation. Nevertheless, predicted discrimination distances of fur colouration were virtually indistinguishable for mammalian and low for avian vision model, which implies effective camouflage.Our study provides one of the best documented cases of multilevel camouflage accuracy in geographically widespread taxa. We conclude that background matching has become an effective and common adaptation against predatory threat in Sahara–Sahelian desert rodents. [ABSTRACT FROM AUTHOR]

The quantum computational models were proposed to study how quantum mechanics influence the power of computing models. A lot of works are already done to extend simpler classical computational models to quantum models like quantum finite automata and quantum pushdown automata. Since the quantum part of a machine is not easy to implement, it is necessary to think about a computational model which minimize the quantum part of the model. Motivated by this fact in this paper we introduce a variation of quantum pushdown automata whose stack and tape head are implemented as classical devices. We observe that this model is powerful than classical pushdown automata and some other quantum computational models. Here we also showed that it can recognize some non context free languages. [ABSTRACT FROM AUTHOR]