Three-dimensional localization of sperm whales using a single hydrophone

2006 ◽  
Vol 120 (4) ◽  
pp. 2355-2365 ◽  
Author(s):  
Christopher O. Tiemann ◽  
Aaron M. Thode ◽  
Janice Straley ◽  
Victoria O’Connell ◽  
Kendall Folkert
Keyword(s):  
Three Dimensional ◽  
Sperm Whales

Three‐dimensional localization of diving sperm whales using a short‐aperture towed horizontal array

2000 ◽  
Vol 108 (5) ◽  
pp. 2540-2540
Author(s):  
Aaron M. Thode ◽  
David K. Mellinger ◽  
Sarah Stienessen ◽  
Anthony Martinez ◽  
Keith D. Mullin
Keyword(s):  
Three Dimensional ◽  
Sperm Whales ◽  
Horizontal Array

On the possibility of detecting surfacing sperm whales at risk of collision using others' foraging clicks

2007 ◽  
Vol 87 (1) ◽  
pp. 47-58 ◽  
Author(s):  
E. Delory ◽  
M. André ◽  
J.-L. Navarro Mesa ◽  
M. van der Schaar
Keyword(s):  
At Risk ◽  
Canary Islands ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Sperm Whale ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Detection Range ◽  
Passive Sonar ◽  
Acoustic Sources

Cetaceans are prone to collisions with fast vessels, and in areas of high cetacean and vessel density such as in the Canary Islands, the sperm whale (Physeter macrocephalus) is of great concern. Sperm whales are highly vocal and can be localized with passive sonar, but, when at or near the surface, they tend to stop vocalizing, i.e. when they are most at risk. Regrettably, ship-borne active solutions have proven inefficient due to the short detection range and the ships' high-speeds. Our objective in this paper is to evaluate the efficiency of an original passive sonar solution that would use vocalizing whale clicks at depth as acoustic sources to detect silent whales. This solution could be a non-invasive complementary component of a more complex passive localization whale anti-collision system. To meet this aim, a simulation tool for 3D acoustic propagation was designed in which a wideband Nx2D ray solution of the wave equation simulates a passive solution consisting of an arbitrary number of active acoustic sources, an illuminated object, and a receiver, all positioned in a three-dimensional space with arbitrary bathymetry. Both curved and straight ray solutions were implemented, the latter providing greater computational speeds at the expense of temporal and angular precision. The software recreates the resulting sound mixture of direct, reverberated and target back-scattered signals arriving at the array sensors for any array configuration, any number of sources and one target. Simulations show the application of the concept for the Canary Islands, with a detection range upper bound of the order of one kilometre.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

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