Possible Role of Polarized Light Information in Spatial Recognition in the Cricket Gryllus bimaculatus

2021 ◽  
Vol 38 (4) ◽  
Author(s):  
Nobuaki Matsubara ◽  
Ryuichi Okada ◽  
Midori Sakura
Keyword(s):  
Polarized Light ◽  
Gryllus Bimaculatus ◽  
Spatial Recognition

scholarly journals Exciton-to-trion conversion as a control mechanism for valley polarization in room-temperature monolayer WS2

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Joris J. Carmiggelt ◽  
Michael Borst ◽  
Toeno van der Sar
Keyword(s):  
Room Temperature ◽  
Polarized Light ◽  
Optical Excitation ◽  
Equation Model ◽  
Chemical Doping ◽  
Transition Metal Dichalcogenide ◽  
Net Charge ◽  
Circularly Polarized Light ◽  
Valley Polarization

Abstract Transition metal dichalcogenide (TMD) monolayers are two-dimensional semiconductors with two valleys in their band structure that can be selectively addressed using circularly polarized light. Their photoluminescence spectrum is characterized by neutral and charged excitons (trions) that form a chemical equilibrium governed by the net charge density. Here, we use chemical doping to drive the conversion of excitons into trions in $$\text {WS}_{2}$$ WS 2 monolayers at room temperature, and study the resulting valley polarization via photoluminescence measurements under valley-selective optical excitation. We show that the doping causes the emission to become dominated by trions with a strong valley polarization associated with rapid non-radiative recombination. Simultaneously, the doping results in strongly quenched but highly valley-polarized exciton emission due to the enhanced conversion into trions. A rate equation model explains the observed valley polarization in terms of the doping-controlled exciton-trion equilibrium. Our results shed light on the important role of exciton-trion conversion on valley polarization in monolayer TMDs.

scholarly journals Cleaner wrasse indirectly affect the cognitive performance of a damselfish through ectoparasite removal

2018 ◽  
Vol 285 (1874) ◽  
pp. 20172447 ◽  
Author(s):  
Sandra A. Binning ◽  
Dominique G. Roche ◽  
Alexandra S. Grutter ◽  
Simona Colosio ◽  
Derek Sun ◽  
...  
Keyword(s):  
Cognitive Abilities ◽  
Visual Discrimination ◽  
Negative Impact ◽  
Cognitive Impairments ◽  
Discrimination Performance ◽  
Innate Immune ◽  
Discrimination Test ◽  
Pomacentrus Amboinensis ◽  
Spatial Recognition

Cleaning organisms play a fundamental ecological role by removing ectoparasites and infected tissue from client surfaces. We used the well-studied cleaning mutualisms involving the cleaner wrasse, Labroides dimidiatus, to test how client cognition is affected by ectoparasites and whether these effects are mitigated by cleaners. Ambon damselfish ( Pomacentrus amboinensis) collected from experimental reef patches without cleaner wrasse performed worse in a visual discrimination test than conspecifics from patches with cleaners. Endoparasite abundance also negatively influenced success in this test. Visual discrimination performance was also impaired in damselfish experimentally infected with gnathiid (Crustacea: Isopoda) ectoparasites. Neither cleaner absence nor gnathiid infection affected performance in spatial recognition or reversal learning tests. Injection with immune-stimulating lipopolysaccharide did not affect visual discrimination performance relative to saline-injected controls, suggesting that cognitive impairments are not due to an innate immune response. Our results highlight the complex, indirect role of cleaning organisms in promoting the health of their clients via ectoparasite removal and emphasize the negative impact of parasites on host's cognitive abilities.

The Role of Microscopy in the Study of Chemical Polymorphism

2000 ◽  
Vol 6 (S2) ◽  
pp. 1000-1001
Author(s):  
R.A. Carlton
Keyword(s):  
Solid State ◽  
Development Process ◽  
Polarized Light ◽  
Crystal Form ◽  
Chemical Polymorphism ◽  
Optic Angle ◽  
Temperature And Pressure ◽  
Metastable Forms ◽  
The Relationship

Chemical polymorphism refers to the ability of compounds to exist in different solid state forms. In general, these differ solely in their arrangement in space (i.e., their crystal form). Polymorphs typically have different solid state properties such as melting point, solubility, density, etc. They also commonly exhibit distinctive optical properties such as refractive index, extinction position, optic sign and optic angle. The choice of polymorph can be an important consideration in the drug development process if the solid state properties have wide differences. Further, it is generally desirable to develop the polymorph which is stable at room temperature and pressure, since metastable forms convert spontaneously to the stable ones, albeit often at a very slow rate. Optical, thermal and scanning electron microscopy each play important roles in the study of chemical polymorphism.Optical microscopy, and more specifically polarized light microscopy, contributes both to the discovery of new polymorphs and to the elucidation of the relationship among polymorphs.

scholarly journals Behavioural relevance of polarization sensitivity as a target detection mechanism in cephalopods and fishes

2011 ◽  
Vol 366 (1565) ◽  
pp. 734-741 ◽  
Author(s):  
Vincenzo Pignatelli ◽  
Shelby E. Temple ◽  
Tsyr-Huei Chiou ◽  
Nicholas W. Roberts ◽  
Shaun P. Collin ◽  
...  
Keyword(s):  
Target Detection ◽  
Polarized Light ◽  
Luminance Contrast ◽  
Polarization Sensitivity ◽  
Prey Detection ◽  
Free Swimming ◽  
Detection Mechanism ◽  
Set Up ◽  
Polarization Of Light

Aquatic habitats are rich in polarized patterns that could provide valuable information about the environment to an animal with a visual system sensitive to polarization of light. Both cephalopods and fishes have been shown to behaviourally respond to polarized light cues, suggesting that polarization sensitivity (PS) may play a role in improving target detection and/or navigation/orientation. However, while there is general agreement concerning the presence of PS in cephalopods and some fish species, its functional significance remains uncertain. Testing the role of PS in predator or prey detection seems an excellent paradigm with which to study the contribution of PS to the sensory assets of both groups, because such behaviours are critical to survival. We developed a novel experimental set-up to deliver computer-generated, controllable, polarized stimuli to free-swimming cephalopods and fishes with which we tested the behavioural relevance of PS using stimuli that evoke innate responses (such as an escape response from a looming stimulus and a pursuing behaviour of a small prey-like stimulus). We report consistent responses of cephalopods to looming stimuli presented in polarization and luminance contrast; however, none of the fishes tested responded to either the looming or the prey-like stimuli when presented in polarization contrast.

ON THE BEHAVIOR OF POLARIZED LIGHT IN TWIST-ORIENTED NEMATIC LIQUID CRYSTALS WITH ANISOTROPIC ABSORBENT DYE

2020 ◽  
Vol 54 (1 (251)) ◽  
pp. 56-60
Author(s):  
H.H. Hovakimyan
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Azimuthal Angle ◽  
Polarized Light ◽  
Transmitted Light ◽  
Propagation Of Light ◽  
Linearly Polarized ◽  
Incoming Light

In this work we study the propagation of light in a twist-oriented pleochroic nematic liquid crystal with pleochroic dye. The dependence of the intensity of transmitted light on the azimuthal angle of the linearly polarized incoming light has been investigated experimentally. As a result, the role of absorption anisotropy has been identified.

scholarly journals Functional analysis of the role of eyes absent and sine oculis in the developing eye of the cricket Gryllus bimaculatus

2012 ◽  
Vol 54 (2) ◽  
pp. 227-240 ◽  
Author(s):  
Akira Takagi ◽  
Kazuki Kurita ◽  
Taiki Terasawa ◽  
Taro Nakamura ◽  
Tetsuya Bando ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Gryllus Bimaculatus ◽  
Eyes Absent ◽  
Sine Oculis
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