scholarly journals Morphological facilitators for vocal learning explored through the syrinx anatomy of a basal hummingbird

2020 ◽  
Author(s):  
Amanda Monte ◽  
Alexander F. Cerwenka ◽  
Bernhard Ruthensteiner ◽  
Manfred Gahr ◽  
Daniel N. Düring
Keyword(s):  
Sound Production ◽  
Three Dimensional ◽  
Vocal Learning ◽  
Dimensional Structure ◽  
Micro Computed Tomography ◽  
Vocal Production ◽  
Precise Control ◽  
Acoustic Space ◽  
Biomechanical Factors ◽  
Intrinsic Musculature

AbstractVocal learning is a rare evolutionary trait that evolved independently in three avian clades: songbirds, parrots, and hummingbirds. Although the anatomy and mechanisms of sound production in songbirds are well understood, little is known about the hummingbird’s vocal anatomy. We use high-resolution micro-computed tomography (μCT) and microdissection to reveal the three-dimensional structure of the syrinx, the vocal organ of the black jacobin (Florisuga fusca), a phylogenetically basal hummingbird species. We identify three unique features of the black jacobin’s syrinx: (i) a shift in the position of the syrinx to the outside of the thoracic cavity and the related loss of the sterno-tracheal muscle, (ii) complex intrinsic musculature, oriented dorso-ventrally, and (iii) ossicles embedded in the medial vibratory membranes. Their syrinx morphology allows vibratory decoupling, precise control of complex acoustic parameters, and a large redundant acoustic space that may be key biomechanical factors facilitating the occurrence of vocal production learning.

Visualization of a pillar-shaped fiber bundle in a model needle-punched nonwoven fabric using X-ray micro-computed tomography

2016 ◽  
Vol 87 (11) ◽  
pp. 1387-1393 ◽  
Author(s):  
Tatsuya Ishikawa ◽  
KyoungHou Kim ◽  
Yutaka Ohkoshi
Keyword(s):  
Fiber Bundle ◽  
Three Dimensional ◽  
Nonwoven Fabric ◽  
Fiber Bundles ◽  
Dimensional Structure ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Needle Punching ◽  
Pet Fibers ◽  
Polyethylene Fibers

In the needle-punching process, the barbs of a needle catch fibers and orient them along the thickness direction of the fabric. The oriented fibers form a pillar-shaped fiber bundle, which acts as a bonding point of the fabric. The structure of the pillar-shaped fiber bundle thus governs the mechanical properties of needle-punched nonwoven fabric, and both are largely affected by the needle-punching conditions. However, the three-dimensional structure of pillar-shaped fiber bundles and their development under different needle-punching conditions have not been revealed. In the present study, we visualized the three-dimensional structure of a pillar-shaped fiber bundle in needle-punched nonwoven fabric, employing X-ray micro-computed tomography (XCT) on the basis of the difference in the X-ray absorption coefficient between polyethylene terephthalate (PET) and polyethylene fibers. For a material density ratio of less than 1.4 and PET fibers having a diameter of 40 µm, the pillar-shaped bundles of PET fibers were visualized by erasing 20-µm polyethylene fibers in XCT images. Furthermore, we investigated the effects of the penetration depth of the needle on the development of pillar-shaped fiber bundles. The number of fibers constituting a pillar largely increased at a penetration depth of 19.0 mm, and pillars protruded from the bottom surface of the fabric and formed a stitch structure. The XCT applied in this study is thus effective in analyzing the structure of pillar-shaped fiber bundles quantitatively without affecting the structure of the nonwoven fabric.

scholarly journals Three-dimensional wing structure attenuates aerodynamic efficiency in flapping fly wings

2020 ◽  
Vol 17 (164) ◽  
pp. 20190804 ◽  
Author(s):  
Thomas Engels ◽  
Henja-Niniane Wehmann ◽  
Fritz-Olaf Lehmann
Keyword(s):  
Aerodynamic Force ◽  
Three Dimensional ◽  
Force Production ◽  
Reynolds Numbers ◽  
Dimensional Structure ◽  
Micro Computed Tomography ◽  
Venation Pattern ◽  
Aerodynamic Pressure ◽  
Inertial Loading ◽  
External Forces

The aerial performance of flying insects ultimately depends on how flapping wings interact with the surrounding air. It has previously been suggested that the wing's three-dimensional camber and corrugation help to stiffen the wing against aerodynamic and inertial loading during flapping motion. Their contribution to aerodynamic force production, however, is under debate. Here, we investigated the potential benefit of three-dimensional wing shape in three different-sized species of flies using models of micro-computed tomography-scanned natural wings and models in which we removed either the wing's camber, corrugation, or both properties. Forces and aerodynamic power requirements during root flapping were derived from three-dimensional computational fluid dynamics modelling. Our data show that three-dimensional camber has no benefit for lift production and attenuates Rankine–Froude flight efficiency by up to approximately 12% compared to a flat wing. Moreover, we did not find evidence for lift-enhancing trapped vortices in corrugation valleys at Reynolds numbers between 137 and 1623. We found, however, that in all tested insect species, aerodynamic pressure distribution during flapping is closely aligned to the wing's venation pattern. Altogether, our study strongly supports the assumption that the wing's three-dimensional structure provides mechanical support against external forces rather than improving lift or saving energetic costs associated with active wing flapping.

Proximity/Infinity

2019 ◽  
pp. 401-418
Author(s):  
Miriama Young
Keyword(s):  
Sound Production ◽  
Vocal Music ◽  
Vocal Production ◽  
Recording Technology ◽  
Recorded Music ◽  
Interior Spaces ◽  
Production Practice ◽  
Production Practices ◽  
Acoustic Space ◽  
The Voice

This chapter looks at the mediated voice and acoustic space, particularly where the voice in recording occupies small interior spaces, termed pod-music. It surveys a range of recorded vocal music to show ways in which contemporary composition, performance, recording, and production practices exploit the personal listening environment that headphones and mobile listening enable. Not only is our experience of the recorded voice mediated and shaped by the devices on which we record and audition them, but vocal and sound production practice are in turn shaped by these technologies. Further, mediation of recording technology and transmission impacts how we hear the voice as proximal, intimate, or infinite in various contexts. The discussion begins with headphone listening before turning to the creation of recorded music: vocal production, recording, and the aesthetics of postproduction for interior modes of dissemination.

scholarly journals Killer whales are capable of vocal learning

2006 ◽  
Vol 2 (4) ◽  
pp. 509-512 ◽  
Author(s):  
Andrew D Foote ◽  
Rachael M Griffin ◽  
David Howitt ◽  
Lisa Larsson ◽  
Patrick J.O Miller ◽  
...  
Keyword(s):  
Sound Production ◽  
Vocal Learning ◽  
Physical Structure ◽  
Learning Ability ◽  
Killer Whales ◽  
Sea Lion ◽  
California Sea Lion ◽  
Vocal Production ◽  
Vocal Behaviour ◽  
Call Usage

The production learning of vocalizations by manipulation of the sound production organs to alter the physical structure of sound has been demonstrated in only a few mammals. In this natural experiment, we document the vocal behaviour of two juvenile killer whales, Orcinus orca , separated from their natal pods, which are the only cases of dispersal seen during the three decades of observation of their populations. We find mimicry of California sea lion ( Zalophus californianus ) barks, demonstrating the vocal production learning ability for one of the calves. We also find differences in call usage (compared to the natal pod) that may reflect the absence of a repertoire model from tutors or some unknown effect related to isolation or context.

scholarly journals Differentiated appendages in Isoxys illuminate origin of arthropodization

2021 ◽  
Author(s):  
Caixia Zhang ◽  
Yu Liu ◽  
Javier Ortega-Hernández ◽  
Joanna Wolfe ◽  
Changfei Jin ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Phylogenetic Position ◽  
Burgess Shale ◽  
Micro Computed Tomography ◽  
Major Transition ◽  
New Material ◽  
Feeding Function ◽  
Chengjiang Biota ◽  
First Time

Abstract The Cambrian fossil record has produced remarkable insights into the origin of euarthropods, particularly the evolution of their versatile body plan of segments bearing specialized, jointed appendages for different functions including feeding and locomotion [01, 02]. Early euarthropod evolution involved a major transition from lobopodian-like taxa [03, 04, 05] to organisms featuring a fully sclerotized trunk (arthrodization) and limbs (arthropodization) [02, 06, 07, 08]. However, the precise origin of arthropodization remains controversial because some of the earliest branching euarthropods possess a broad dorsal carapace that obscures critical details of the trunk and appendage organization [09, 10, 11, 12, 13, 14, 15]. Here, we demonstrate the presence of fully arthropodized ventral appendages in the upper stem-group euarthropod Isoxys curvirostratus from the early Cambrian Chengjiang biota in South China. Micro-computed tomography reveals the detailed three-dimensional structure of the biramous appendages in I. curvirostratus for the first time. In addition to the raptorial frontal appendages I. curvirostratus also possesses two batches of morphologically distinct biramous limbs, with the first batch consisting of four pairs of short cephalic appendages bearing prominent endites with a feeding function, followed by a second batch of elongate trunk appendages for locomotion. Each biramous limb bears an endopod with more than 12 well-defined podomeres, and an exopod consisting of a slender shaft carrying approximately a dozen paddle-shaped lamellae. Our findings clarify the enigmatic appendicular organization of Isoxys, one of the most ubiquitous euarthropods in Cambrian Burgess Shale-type deposits worldwide [01, 10, 11, 12, 14, 15, 16, 17, 18]. Critically, our new material shows that the trunk of I. curvirostratus was not arthrodized. The phylogenetic position of isoxyiids as possibly the earliest branching members of Deuteropoda [01, 02, 07, 15, 19], suggests that arthropodized biramous appendages evolved before the pattern of full trunk arthrodization that characterizes most extant and extinct members of this successful animal phylum.

scholarly journals A researcher's guide to the comparative assessment of vocal production learning

2021 ◽  
Vol 376 (1836) ◽  
pp. 20200237
Author(s):  
Ella Z. Lattenkamp ◽  
Stephen G. Hörpel ◽  
Janine Mengede ◽  
Uwe Firzlaff
Keyword(s):  
Sound Production ◽  
Production Systems ◽  
Experimental Studies ◽  
Vocal Learning ◽  
Comparative Assessment ◽  
Theme Issue ◽  
Acoustic Parameters ◽  
Animal Kingdom ◽  
Vocal Production ◽  
Five Factors

Vocal production learning (VPL) is the capacity to learn to produce new vocalizations, which is a rare ability in the animal kingdom and thus far has only been identified in a handful of mammalian taxa and three groups of birds. Over the last few decades, approaches to the demonstration of VPL have varied among taxa, sound production systems and functions. These discrepancies strongly impede direct comparisons between studies. In the light of the growing number of experimental studies reporting VPL, the need for comparability is becoming more and more pressing. The comparative evaluation of VPL across studies would be facilitated by unified and generalized reporting standards, which would allow a better positioning of species on any proposed VPL continuum. In this paper, we specifically highlight five factors influencing the comparability of VPL assessments: (i) comparison to an acoustic baseline, (ii) comprehensive reporting of acoustic parameters, (iii) extended reporting of training conditions and durations, (iv) investigating VPL function via behavioural, perception-based experiments and (v) validation of findings on a neuronal level. These guidelines emphasize the importance of comparability between studies in order to unify the field of vocal learning. This article is part of the theme issue ‘Vocal learning in animals and humans’.

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