Under 502 nm turquoise light combined with 590 nm yellow light and in total darkness, European robins, Erithacus rubecula, no longer prefer their migratory direction, but exhibit so-called fixed direction responses that do not show the seasonal change between spring and autumn. We tested robins under these light conditions in the local geomagnetic field of 46 microT, a field of twice this intensity, 92 microT, and a field of three times this intensity, 138 microT. Under all three magnetic conditions, the birds preferred the same easterly direction under turquoise-and-yellow light and the same northwesterly direction under dark, while they were oriented in their seasonally appropriate direction under control conditions. "Fixed direction" responses are thus not limited to a narrow intensity window as has been found for normal compass orientation. This can be attributed to their origin in the magnetite-based receptor in the upper beak, which operates according to fundamentally different principles than the radical pair mechanism in the retina mediating compass orientation. "Fixed direction" responses are possibly a relict of a receptor mechanism that changed its function, now mainly providing information on magnetic intensity.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1007/s00114-009-0608-8 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
High-Energy Density Pure Polyvinylidene Difluoride with the Magnetic Field Modulation of Free-Volume Pore Size and Other Microstructures.
Polymers (Basel)
October 2024
School of Physics and Electronic Engineering, Northeast Petroleum University, No. 199, Fazhan Road, Daqing 163318, China.
PVDF polymer dielectrics, renowned for their ultra-high-power density, ultra-fast response times, remarkable toughness, and lightweight properties, constitute the essential material foundation for the development of dielectric capacitors. Nevertheless, the low-energy density of these dielectrics presents a challenge to the advancement of dielectric capacitors. In this paper, in the process of preparing monolayer pure PVDF dielectric films by the solution casting method, a fixed-direction magnetic field and a rotating magnetic field were introduced in the horizontal direction, respectively, and this investigation explores the impact of magnetic field modulation on the polymer films' free-volume pore size, grain size, phase structure, dielectric properties, and energy storage capabilities by altering the duration and orientation of the magnetic field's influence.
View Article and Find Full Text PDFNumerical model of the locomotion of oscillating 'robots' with frictional anisotropy on differently-structured surfaces.
Sci Rep
August 2024
Department of Functional Morphology and Biomechanics, Zoological Institute of the Kiel University, Am Botanischen Garten 1-9, 24098, Kiel, Germany.
In engineering materials, surface anisotropy is known in certain textured patterns that appear during the manufacturing process. In biology, there are numerous examples of mechanical systems which combine anisotropic surfaces with the motion, elicited due to some actuation using muscles or stimuli-responsive materials, such as highly ordered cellulose fiber arrays of plant seeds. The systems supplemented by the muscles are rather fast actuators, because of the relatively high speed of muscle contraction, whereas the latter ones are very slow, because they generate actuation depending on the daily changes in the environmental air humidity.
View Article and Find Full Text PDFDynamic continualization of mechanical metamaterials with quasi-periodic microstructure.
Philos Trans A Math Phys Eng Sci
September 2024
Department DICCA, University of Genova, via Montallegro 1 , Genova, Italy.
This article focuses on characterizing a class of quasi-periodic metamaterials created through the repeated arrangement of an elementary cell in a fixed direction. The elementary cell consists of two building blocks made of elastic materials and arranged according to the generalized Fibonacci sequence, giving rise to a quasi-periodic finite microstructure, also called Fibonacci generation. By exploiting the transfer matrix method, the frequency band structure of selected periodic approximants associated with the Fibonacci superlattice, i.
View Article and Find Full Text PDFWe introduce the notion of a "walk with jumps", which we conceive as an evolving process in which a point moves in a space (for us, typically $\mathbb{H}^2$) over time, in a consistent direction and at a consistent speed except that it is interrupted by a finite set of "jumps" in a fixed direction and distance from the walk direction. Our motivation is biological; specifically, to use walks with jumps to encode the activity of a neuron over time (a ``spike train``). Because (in $\mathbb{H}^2$) the walk is built out of a sequence of transformations that do not commute, the walk's endpoint encodes aspects of the sequence of jump times beyond their total number, but does so incompletely.
View Article and Find Full Text PDFSelective directional liquid transport on shoot surfaces of .
Science
June 2024
Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR 999077, P. R. China.
Directional liquid transport has been widely observed in various species including cacti, spiders, lizards, the pitcher plant , and leaves. However, in all these examples the liquid transport for a specific liquid is completely restricted in a fixed direction. We demonstrate that shoot surfaces have the ability to transport a specific liquid unidirectionally in either direction.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!