scholarly journals Vertical escape tactics and movement potential of orthoconic cephalopods

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11797
Author(s):  
David J. Peterman ◽  
Kathleen A. Ritterbush
Keyword(s):  
Motion Tracking ◽  
Metabolic Cost ◽  
Vertical Displacement ◽  
Mantle Cavity ◽  
Hydrodynamic Drag ◽  
Order Constraints ◽  
Life Habits ◽  
3D Printed ◽  
Negative Buoyancy ◽  
High Output

Measuring locomotion tactics available to ancient sea animals can link functional morphology with evolution and ecology over geologic timescales. Externally-shelled cephalopods are particularly important for their central roles in marine trophic exchanges, but most fossil taxa lack sufficient modern analogues for comparison. In particular, phylogenetically diverse cephalopods produced orthoconic conchs (straight shells) repeatedly through time. Persistent re-evolution of this morphotype suggests that it possesses adaptive value. Practical lateral propulsion is ruled out as an adaptive driver among orthoconic cephalopods due to the stable, vertical orientations of taxa lacking sufficient counterweights. However, this constraint grants the possibility of rapid (or at least efficient) vertical propulsion. We experiment with this form of movement using 3D-printed models of Baculites compressus, weighted to mimic hydrostatic properties inferred by virtual models. Furthermore, model buoyancy was manipulated to impart simulated thrust within four independent scenarios (Nautilus-like cruising thrust; a similar thrust scaled by the mantle cavity of Sepia; sustained peak Nautilus-like thrust; and passive, slightly negative buoyancy). Each model was monitored underwater with two submerged cameras as they rose/fell over ~2 m, and their kinematics were computed with 3D motion tracking. Our results demonstrate that orthocones require very low input thrust for high output in movement and velocity. With Nautilus-like peak thrust, the model reaches velocities of 1.2 m/s (2.1 body lengths per second) within one second starting from a static initial condition. While cephalopods with orthoconic conchs likely assumed a variety of life habits, these experiments illuminate some first-order constraints. Low hydrodynamic drag inferred by vertical displacement suggests that vertical migration would incur very low metabolic cost. While these cephalopods likely assumed low energy lifestyles day-to-day, they may have had a fighting chance to escape from larger, faster predators by performing quick, upward dodges. The current experiments suggest that orthocones sacrifice horizontal mobility and maneuverability in exchange for highly streamlined, vertically-stable, upwardly-motile conchs.

scholarly journals Isolating the Energetic and Mechanical Consequences of Imposed Reductions in Ankle and Knee Flexion during Gait.

2021 ◽  
Author(s):  
Emily McCain ◽  
Theresa Libera ◽  
Matthew Berno ◽  
Gregory Sawicki ◽  
Katherine Saul ◽  
...  
Keyword(s):  
Metabolic Cost ◽  
Relative Increase ◽  
Joint Motion ◽  
Knee Motion ◽  
Ankle Motion ◽  
Gait Characteristics ◽  
Joint Range Of Motion ◽  
3D Printed ◽  
Ankle Function ◽  
Joint Range

Abstract Background: Weakness of ankle and knee musculature following injury or disorder results in reduced joint motion associated with metabolically expensive gait compensations to enable limb support and advancement. However, neuromechanical coupling between the ankle and knee make it difficult to discern independent roles of these restrictions in joint motion on compensatory mechanics and metabolic penalties.Methods: We sought to determine relative impacts of ankle and knee impairment on compensatory gait strategies and energetic outcomes using an unimpaired cohort (N=15) with imposed unilateral joint range of motion restrictions as a surrogate for reduced motion resulting from gait pathology. Participants walked on a dual-belt instrumented treadmill at 0.8 m s-1 using a 3D printed ankle stay and a knee brace to systematically limit ankle motion (restricted-ank), knee motion (restricted-knee), and ankle and knee motion (restricted-a+k) simultaneously. In addition, participants walked without any ankle or knee bracing (control) and with knee bracing worn but unrestricted (braced).Results: When ankle motion was restricted (restricted-ank, restricted-a+k) we observed decreased peak propulsion relative to the braced condition on the restricted limb. Reduced knee motion (restricted-knee, restricted-a+k) increased restricted limb circumduction relative to the restricted-ank condition through ipsilateral hip hiking. Interestingly, restricted limb average positive hip power increased in the restricted-ank condition but decreased in the restricted-a+k and restricted-knee conditions, suggesting that locking the knee impeded hip compensation. As expected, reduced ankle motion, either without (restricted-ank) or in addition to knee restriction (restricted-a+k) yielded significant increase in net metabolic rate when compared with the braced condition. Furthermore, the relative increase in metabolic cost was significantly larger with restricted-a+k when compared to restricted-knee condition.Conclusions: Our methods allowed for the reproduction of asymmetric gait characteristics including reduced propulsive symmetry and increased circumduction. The metabolic consequences bolster the potential energetic benefit of targeting ankle function during rehabilitation.

MIND THE GAPE: THE SOLUTION TO THE LIFE HABITS OF RAFINESQUINA ALTERNATA MAY TURN ON A 3D-PRINTED HINGE

2018 ◽  
Author(s):  
Benjamin Dattilo ◽  
◽  
Aaron Morse ◽  
Keith Dewing ◽  
James W. Hagadorn
Keyword(s):  
Turn On ◽  
Life Habits ◽  
3D Printed

scholarly journals Stable hooks: biomechanics of heteromorph ammonoids with U-shaped body chambers

2020 ◽  
Vol 86 (4) ◽  
pp. 267-279
Author(s):  
David J Peterman ◽  
Ryan Shell ◽  
Charles N Ciampaglio ◽  
Margaret M Yacobucci
Keyword(s):  
Intermediate Stage ◽  
Physical Models ◽  
Mature Stage ◽  
Hydrodynamic Drag ◽  
Centre Of Mass ◽  
Neutral Buoyancy ◽  
Selective Pressures ◽  
Adult Model ◽  
3D Printed ◽  
Neutrally Buoyant

ABSTRACT The biomechanics of uncoiled heteromorph ammonoids with body chambers that terminate in U-shaped hooks (ancylocones) were investigated with virtual and physical models of Audouliceras renauxianum. Virtual models were used to compute the hydrostatic properties of this morphotype. Audouliceras has the capacity for neutral buoyancy and this suggests that other taxa with similar proportions had this ability as well. Hydrostatic stability gradually increases during ontogeny, coincident with the larger degree of uncoiling. The juvenile planispiral stage has a similar stability and apertural orientation to the extant Nautilus. The adult stage, however, undergoes an increase in stability by a factor of over 3, while assuming an upward-facing posture. Counterintuitively, the stage during the formation of the shaft (before the growth of the U-shaped hook) is oriented horizontally. This intermediate stage would have had poor horizontal mobility due to the positioning of the hyponome below the centre of mass. The juvenile planispiral stage and mature stage, however, would have been well suited to horizontal backward movement with minimal rocking. Ancylocones are generally thought of as quasiplanktic vertical migrants. Thus, their relative horizontal swimming ability has been largely disregarded. Experiments on 3D printed, neutrally buoyant physical models reveal that hydrodynamic drag is indeed larger compared to Nautilus. However, Audouliceras could reach similar maximum horizontal velocities depending on the available thrust. Sepia-like thrusts yield velocities similar to equivalently sized Nautilus (c. 15 cm/s), while Nautilus-like thrusts yield velocities not much lower (c. 11 cm/s). Due to the hydrostatic properties of the ancylocone, the adult model undergoes less rocking (±4.5°) during movement than Nautilus (±10°). The minimal hydrodynamic consequences for ancylocones suggest that stability, orientation and directional efficiency are key selective pressures for some heteromorph shells, which may have primarily served as hydrostatic devices.

Optimum gradient of mountain paths

1995 ◽  
Vol 79 (5) ◽  
pp. 1698-1703 ◽  
Author(s):  
A. E. Minetti
Keyword(s):  
Energy Expenditure ◽  
High Altitude ◽  
Body Mass ◽  
Metabolic Cost ◽  
Vertical Displacement ◽  
Transmission Efficiency ◽  
Metabolic Power ◽  
Gait Biomechanics ◽  
Overall Efficiency ◽  
Downhill Walking

By combining the experiment results of R. Margaria (Atti Accad. Naz. Lincei Memorie 7: 299–368, 1938), regarding the metabolic cost of gradient locomotion, together with recent insights on gait biomechanics, a prediction about the most economical gradient of mountain paths (approximately 25%) is obtained and interpreted. The pendulum-like mechanism of walking produces a waste of mechanical work against gravity within the gradient range of up to 15% (the overall efficiency is dominated by the low transmission efficiency), whereas for steeper values only the muscular efficiency is responsible for the (slight) metabolic change (per meter of vertical displacement) with respect to gradient. The speeds at the optimum gradient turned out to be approximately 0.65 m/s (+0.16 m/s vertical) and 1.50 m/s (-0.36 m/s vertical), for uphill and downhill walking, respectively, and the ascensional energy expenditure was 0.4 and 2.0 ml O2.kg body mass-1.vertical m-1 climbed or descended. When the metabolic power becomes a burden, as in high-altitude mountaineering, the optimum gradient should be reduced. A sample of real mountain path gradients, experimentally measured, mimics the obtained predictions.

scholarly journals Aqueous particle generation with a 3D printed nebulizer

2020 ◽  
Author(s):  
Michael Rösch ◽  
Daniel J. Cziczo
Keyword(s):  
Ammonium Sulfate ◽  
Aqueous Media ◽  
Cost Effective ◽  
Polystyrene Latex ◽  
Particle Generation ◽  
Output Stability ◽  
Sulfate Solutions ◽  
3D Printed ◽  
Design And Testing ◽  
High Output

Abstract. In this study, we describe the design and testing of a high output stability constant liquid feed nebulizer using the Venturi principle to generate liquid particles from solutions. This atomizer, the PRinted drOpleT Generator (PROTeGE) was manufactured using stereolithography (SLA) printing. Different concentrations of ammonium sulfate solutions were used to characterize the size and number concentration of the generated particles. A comparison of a 3D printed 0.5 mm orifice with a more dimensionally accurate and symmetric machined 0.5 mm brass orifice using the same ammonium sulfate solutions was also performed. PROTeGE is also shown to be capable of dispersing polystyrene latex spheres (PSLs) for calibration purposes. The particle number concentrations obtained in this study ranged from ~10 000 cm−3 for 0.75 micrometer to ~100 cm−3 for 5.0 micrometer PSL particles with a dependence on the concentration of the dispersed solution. PROTeGE is easy to manufacture and operate, low in maintenance, and cost-effective for laboratory and field generation of particles from aqueous media.

Kinematics of the Human Pelvis Following Open Book Injury

2002 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Mohamed Samir Hefzy ◽  
Nabil Ebraheim ◽  
Anis Mekhail ◽  
Richard Yeasting
Keyword(s):  
Motion Tracking ◽  
Articular Surface ◽  
Tracking System ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
X Rays ◽  
Open Book ◽  
Sacroiliac Joints ◽  
Pure Rotation ◽  
Planar Surfaces

The objective of this study is to determine the three dimensional kinematics of the human pelvis including both sacroiliac joints following a simulated open book fracture induced on cadavers by applying anterior-posterior compressive loads to the pelvis. An electromagnetic digitizing and motion tracking system was utilized to measure the morphology of the pelvis and the relative movements of its bones during this simulated open book fracture. The screw displacement axis method was used to describe the relative motions between the sacrum and each hip bone. Morphologically, it was found that the articular surfaces forming the sacroiliac joints can be approximated with planar surfaces directed from proximal and lateral to distal and medial and from posteromedial to anterolateral. The kinematic data indicate that the motion of the hip bone with respect to the sacrum on the side of the sacroiliac joint (SIJ) opening is almost a pure rotation which translates clinically on the A-P x-rays as pure opening of the SIJ without vertical displacement. The average axis of rotation was found to be almost parallel to the SIJ planar articular surface.

Primitive life habits and adaptive significance of the pelecypod form

Paleobiology ◽  
1976 ◽  
Vol 2 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Michael J. S. Tevesz ◽  
Peter L. McCall
Keyword(s):  
Small Body ◽  
Relative Size ◽  
Mantle Cavity ◽  
Shell Morphology ◽  
Suspension Feeding ◽  
Suspension Feeders ◽  
Body Sizes ◽  
Mode Of Life ◽  
Life Habits ◽  
Soft Bottoms

The typical pelecypod form, long thought to be primitively adaptive to burrowing, is likely to have been originally adaptive to a suspension feeding, epifaunal, possibly crawling mode of life. At small body size (< 1 cm), pelecypods possessing typical burrowing features can function as epifaunal crawlers. Pelecypods arose at small body sizes and are part of a molluscan evolutionary sequence in which relative size of the mantle cavity increased to accommodate a few large gills specialized for suspension feeding.Acquisition of a bivalved shell by ancestral epifaunal suspension feeders may have offered protection from sediment clogging on soft bottoms, additional control over the direction, volume, and rate of water flow through the mantle cavity, more effective protection from predators, and better short-term control of the internal environment. Consideration of invertebrate groups analogous to the pelecypods (Branchiopoda, Cladocera, Ostracoda, Phyllocarida) support the view that the bivalve condition is primarily an adaptation for suspension feeding and predator avoidance in benthic environments.The earliest known pelecypod, Fordilla troyensis Barrande, was not necessarily infaunal just because it had features similar to much larger, Recent burrowers. The size, shell morphology and environment of preservation of F. troyensis all suggest that it is reasonable to envision Cambrian pelecypods as epifaunal suspension feeders, possibly crawling on sedimentary bottoms. Moreover, the sudden Ordovician expansion of pelecypods and increase in individual size may be explained as a result of invasion of the infaunal adaptive zone.

The metabolic cost of swimming in marine homeotherms.

1997 ◽  
Vol 200 (3) ◽  
pp. 531-542 ◽  
Author(s):  
A T Hind ◽  
W S Gurney
Keyword(s):  
Metabolic Rate ◽  
Metabolic Cost ◽  
Hydrodynamic Drag ◽  
Cost Of Transport ◽  
Sea Lions ◽  
Minke Whales ◽  
Free And Forced Convection ◽  
Phocid Seals ◽  
Using Data ◽  
The Cost

This paper describes a model of the metabolic cost of swimming in pinnipeds and its application to other marine homeotherms. The model takes account of both hydrodynamic and thermal processes. The thermal component incorporates both free and forced convection and takes account of the effect of hair on free convection. Using data from the literature to evaluate all but two of the parameters, we apply the model to metabolic rate data on phocid seals, otariids (sea lions), penguins and minke whales. We show that the model is able to reproduce two unusual features of the data; namely, a very rapid increase in metabolic rate at low velocities and an overall rise in metabolic rate with velocity which is slower than the rise in hydrodynamic drag force. The work shows the metabolic costs of propulsion and thermoregulation in a swimming homeotherm to be interlinked and suggests differing costs of propulsion for different modes of swimming. This is potentially of ecological significance since the swimming speed that minimises the cost of transport for an animal will change with changes in water temperature.

scholarly journals Isolating the energetic and mechanical consequences of imposed reductions in ankle and knee flexion during gait

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Emily M. McCain ◽  
Theresa L. Libera ◽  
Matthew E. Berno ◽  
Gregory S. Sawicki ◽  
Katherine R. Saul ◽  
...  
Keyword(s):  
Metabolic Cost ◽  
Relative Increase ◽  
Joint Motion ◽  
Knee Motion ◽  
Ankle Motion ◽  
Gait Characteristics ◽  
Joint Range Of Motion ◽  
3D Printed ◽  
Ankle Function ◽  
Joint Range

Abstract Background Weakness of ankle and knee musculature following injury or disorder results in reduced joint motion associated with metabolically expensive gait compensations to enable limb support and advancement. However, neuromechanical coupling between the ankle and knee make it difficult to discern independent roles of these restrictions in joint motion on compensatory mechanics and metabolic penalties. Methods We sought to determine relative impacts of ankle and knee impairment on compensatory gait strategies and energetic outcomes using an unimpaired cohort (N = 15) with imposed unilateral joint range of motion restrictions as a surrogate for reduced motion resulting from gait pathology. Participants walked on a dual-belt instrumented treadmill at 0.8 m s−1 using a 3D printed ankle stay and a knee brace to systematically limit ankle motion (restricted-ank), knee motion (restricted-knee), and ankle and knee motion (restricted-a + k) simultaneously. In addition, participants walked without any ankle or knee bracing (control) and with knee bracing worn but unrestricted (braced). Results When ankle motion was restricted (restricted-ank, restricted-a + k) we observed decreased peak propulsion relative to the braced condition on the restricted limb. Reduced knee motion (restricted-knee, restricted-a + k) increased restricted limb circumduction relative to the restricted-ank condition through ipsilateral hip hiking. Interestingly, restricted limb average positive hip power increased in the restricted-ank condition but decreased in the restricted-a + k and restricted-knee conditions, suggesting that locking the knee impeded hip compensation. As expected, reduced ankle motion, either without (restricted-ank) or in addition to knee restriction (restricted-a + k) yielded significant increase in net metabolic rate when compared with the braced condition. Furthermore, the relative increase in metabolic cost was significantly larger with restricted-a + k when compared to restricted-knee condition. Conclusions Our methods allowed for the reproduction of asymmetric gait characteristics including reduced propulsive symmetry and increased circumduction. The metabolic consequences bolster the potential energetic benefit of targeting ankle function during rehabilitation. Trial registration N/A.

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