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CFD study of hydrodynamic signal perception by fish using the lateral line system / Computational fluid dynamic study of hydrodynamic signal perception by fish using the lateral line systemRapo, Mark Andrew January 2009 (has links)
Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2009. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Includes bibliographical references (leaves 264-277). / The lateral line system on fish has been found to aid in schooling behavior, courtship communication, active and passive hydrodynamic imaging, and prey detection. The most widely used artificial prey stimulus has been the vibrating sphere, which some fish are able to detect even when the signal velocities to its lateral line are orders of magnitude smaller than background current velocities. It is not clear how the fish are able to extract this signal. This thesis uses a series of computational fluid dynamic (CFD) simulations, matched with recent experiments, to quantify the effects of 3D fish body parts on the received dipole signals, and to determine signal detection abilities of the lateral line system in background flow conditions. An approximation is developed for the dipole induced, oscillatory, boundary layer velocity profile over the surface of a fish. An analytic solution is developed for the case when the surface is a wall, and is accurate at points of maximal surface tangential velocity. Results indicate that the flow outside a thin viscous layer remains potential in nature, and that body parts, such as fins, do not significantly affect the received dipole signal in still water conditions. In addition, the canal lateral line system of the sculpin is shown to be over 100 times more sensitive than the superficial lateral line system to high frequency dipole stimuli. Analytical models were developed for the Mottled Sculpin canal and superficial neuromast motions, in response to hydrodynamic signals. When the background flow was laminar, the neuromast motions induced by the stimulus signal at threshold had a spectral peak larger than spectral peaks resulting from the background flow induced motions. / (cont.) When the turbulence level increased, the resulting induced neuromast motions had dominant low frequency oscillations. For fish using the signal encoding mechanisms of phase-locking or spike rate increasing, signal masking should occur. / by Mark Andrew Rapo. / Ph.D.
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Development and functional regeneration of the zebrafish lateral line systemSousa, Filipe Pinto Teixeira 17 February 2012 (has links)
Per a aquesta tesi, utilitzo la línia lateral del peix zebra com a sistema model
per adreçar dues qüestions fonamentals:
En una primera línia d’investigació exploro la relació entre la funció d’un
òrgan i la seva arquitectura. La regeneració de cèl.lules ciliades a la línia
lateral del peix zebra ocorre mitjançant la divisió dels seus progenitors en
determinades posicions dins les zones ventral i dorsal del neuromast. Durant
la regeneració de les cèl.lules ciliades, es forma una línia de simetria vertical,
que bisecciona l’epiteli del neuromast en dues meitats de polaritats planars
oposades. La qüestió de com es controla l’anisotropia de la regeneració de les
cèl.lules ciliades i com integrar aquest procés en l’establiment de la simetria
bilateral d’aquest organ, roman encara per esclarir. En aquest estudi mostro
que la simetria bilateral del neuromast es sosté degut a l’activitat
compartimentalitzada de Notch qui, permetent l’estabilització dels
progenitors de cèl.lules ciliades en compartiments polars específics, organitza
l’anisotropia de la regeneració.
En una segona línia d’investigació, descric el rol del complex de remodelació
de cromatina ATPasa brg1 durant la formació d’organs mecanosensorials al
peix zebra. Així mostro que els mutants de brg1 desenvolupen un sistema de
linia lateral truncat, donat que brg1 es necessari per a la regulació de múltiples
events cel.lulars al primordi de la línia lateral. / In this thesis I use the zebrafish lateral line as a model system to address two
fundamental questions.
In a first line of investigation I explore the relation between an organ
function and its architecture. The regeneration of hair cells in the zebrafish
lateral line occurs trough the division of hair-cell progenitors at specific
locations in the dorsal and ventral aspects of the neuromasts. As hair cells
regenerate a vertical midline that bisects the neuromast epithelium into
perfect mirror-symmetric plane-polarized halves is formed. Each half
contains hair cells of identical planar orientation but opposite to that of the
confronting half. How hair cell regeneration anisotropy is controlled and
how this process is integrated in the establishment of this organ bilateral
symmetry is poorly understood. Here I show that the neuromast bilateral
symmetry is sustained by compartmentalized Notch activity, which governs
regeneration anisotropy by permitting the stabilization of hair cell
progenitors in specific polar compartments.
In a second line of research I report the role of the chromatin remodeling
complex ATPase brg1 during mechanosensory organ formation in the
zebrafish. I show that brg1 mutants develop a truncated lateral line system as
brg1 is needed in the regulation of multiple cellular events in the lateral line
primordium.
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The Sensory Basis of Rheotaxis in Turbulent FlowElder, John Price 03 July 2014 (has links)
No description available.
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