Locomotor energetics in the Indonesian blue‐tongued skink ( Tiliqua gigas ) with implications for the cost of belly‐dragging in early tetrapods

Author(s):  
Edwin Dickinson ◽  
Christopher S. Hanna ◽  
Hannah M. Fischer ◽  
Elizabeth C. Davoli ◽  
Allen A. Currier ◽  
...  
1985 ◽  
Vol 119 (1) ◽  
pp. 149-164 ◽  
Author(s):  
THOMAS L. DANIEL

The influence of unsteady (time varying) motion on the energetics of swimming was investigated with measurements and theoretical estimates of the specific cost of locomotion for two species of hydrozoan medusae: Gonionemus vertens L. Agassiz and Stomotoca atra L. Agassiz. These species, both about 1 g, provide a broad range of swimming speeds for which locomotor energetics can be explored. The cost of locomotion (a dimensionless ratio defined as the rate of energy consumption divided by the product of an animal's weight and speed) was estimated from the oxygen consumption rate of medusae tethered to a force platform. Swimming beat frequency, as monitored by the force platform, was correlated with velocity obtained from ciné-films of freely swimming medusae. The specific cost of locomotion was 6.3 (dimensionless), nearly one order of magnitude greater than the extrapolated cost of locomotion for a vertebrate swimmer of equivalent body mass. The great magnitude of this cost is attributed to two aspects of the periodic pulsatile pattern of locomotion by these cnidarians: (1) the energy expenditure for periodic accelerations of the animal's mass and some mass of fluid about it and (2) the energy dissipated in bell deformations and recovery strokes. Nearly 25% of the augmented cost is attributed to the energy required to overcome an unsteady flow force, that is the force required to accelerate fluid about the animal. Such a high cost of locomotion is apparently a general consequence of swimming with a discontinuous production of thrust. The mechanics of discontinuous swimming are explored by measuring the hydrodynamic coefficients associated with unsteady flows (added-mass coefficients) for models of medusae. The results suggest that the effects of vortex formation and shedding may significantly increase the magnitude of the forces produced by or resisting unsteady animal locomotion.


Author(s):  
James F. Mancuso

IBM PC compatible computers are widely used in microscopy for applications ranging from control to image acquisition and analysis. The choice of IBM-PC based systems over competing computer platforms can be based on technical merit alone or on a number of factors relating to economics, availability of peripherals, management dictum, or simple personal preference.IBM-PC got a strong “head start” by first dominating clerical, document processing and financial applications. The use of these computers spilled into the laboratory where the DOS based IBM-PC replaced mini-computers. Compared to minicomputer, the PC provided a more for cost-effective platform for applications in numerical analysis, engineering and design, instrument control, image acquisition and image processing. In addition, the sitewide use of a common PC platform could reduce the cost of training and support services relative to cases where many different computer platforms were used. This could be especially true for the microscopists who must use computers in both the laboratory and the office.


Author(s):  
H. Rose

The imaging performance of the light optical lens systems has reached such a degree of perfection that nowadays numerical apertures of about 1 can be utilized. Compared to this state of development the objective lenses of electron microscopes are rather poor allowing at most usable apertures somewhat smaller than 10-2 . This severe shortcoming is due to the unavoidable axial chromatic and spherical aberration of rotationally symmetric electron lenses employed so far in all electron microscopes.The resolution of such electron microscopes can only be improved by increasing the accelerating voltage which shortens the electron wave length. Unfortunately, this procedure is rather ineffective because the achievable gain in resolution is only proportional to λ1/4 for a fixed magnetic field strength determined by the magnetic saturation of the pole pieces. Moreover, increasing the acceleration voltage results in deleterious knock-on processes and in extreme difficulties to stabilize the high voltage. Last not least the cost increase exponentially with voltage.


1994 ◽  
Vol 58 (11) ◽  
pp. 832-835 ◽  
Author(s):  
ES Solomon ◽  
TK Hasegawa ◽  
JD Shulman ◽  
PO Walker
Keyword(s):  

1998 ◽  
Vol 138 (2) ◽  
pp. 205-205
Author(s):  
Snellman ◽  
Maljanen ◽  
Aromaa ◽  
Reunanen ◽  
Jyrkinen‐Pakkasvirta ◽  
...  
Keyword(s):  

2004 ◽  
Vol 171 (4S) ◽  
pp. 40-40
Author(s):  
Leslee L. Subak ◽  
Stephen K. Van Den Eeden ◽  
Jeanette S. Brown ◽  
Arona I. Ragins ◽  
Eric Vittinghoff ◽  
...  

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