Three-dimensional odor tracking by Nautilus pompilius

2000 ◽  
Vol 203 (9) ◽  
pp. 1409-1414 ◽  
Author(s):  
J.A. Basil ◽  
R.T. Hanlon ◽  
S.I. Sheikh ◽  
J. Atema
Keyword(s):  
Three Dimensional ◽  
Sensory System ◽  
Three Dimensions ◽  
Odor Source ◽  
Orientation Behavior ◽  
Living Fossil ◽  
Nautilus Pompilius ◽  
Odor Plumes ◽  
Odor Tracking

The ‘living fossil’ Nautilus pompilius is thought to use olfaction as its primary sensory system during foraging, yet neither the organs responsible for olfaction nor the mechanisms or behaviors associated with odor tracking have been subjected to experimentation. Flume testing under dark conditions revealed that Nautilus could consistently detect and follow turbulent odor plumes to the source over distances up to 10 m, exhibiting two types of orientation behavior while sampling in three dimensions. The paired rhinophores were necessary for orientation behavior: when they were temporarily blocked either uni- or bilaterally, Nautilus detected odor but could not track the plume and locate the source. Animals that were tested post-blockage were able to track and locate the source. The role of the 90 thin tentacles remains enigmatic; they seemed to be able to detect odor, but they were not capable of guiding orientation behavior towards a distant odor source. Bilateral chemical sensing by rhinophores in three dimensions may have been the Umwelt of ammonites and belemnites before the evolution of complex eyes and fast locomotion in modern coleoids.

scholarly journals Three-dimensional multi-source localization of underwater objects using convolutional neural networks for artificial lateral lines

2020 ◽  
Vol 17 (162) ◽  
pp. 20190616 ◽  
Author(s):  
Ben J. Wolf ◽  
Jos van de Wolfshaar ◽  
Sietse M. van Netten
Keyword(s):  
Neural Network ◽  
Source Localization ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Sensory System ◽  
Three Dimensions ◽  
Hydrodynamic Theory ◽  
Multiple Sources ◽  
Combined System ◽  
Lateral Lines

This research focuses on the signal processing required for a sensory system that can simultaneously localize multiple moving underwater objects in a three-dimensional (3D) volume by simulating the hydrodynamic flow caused by these objects. We propose a method for localization in a simulated setting based on an established hydrodynamic theory founded in fish lateral line organ research. Fish neurally concatenate the information of multiple sensors to localize sources. Similarly, we use the sampled fluid velocity via two parallel lateral lines to perform source localization in three dimensions in two steps. Using a convolutional neural network, we first estimate a two-dimensional image of the probability of a present source. Then we determine the position of each source, via an automated iterative 3D-aware algorithm. We study various neural network architectural designs and different ways of presenting the input to the neural network; multi-level amplified inputs and merged convolutional streams are shown to improve the imaging performance. Results show that the combined system can exhibit adequate 3D localization of multiple sources.

Boundary layer over a blunt body at low incidence with circumferential reversed flow

1975 ◽  
Vol 72 (1) ◽  
pp. 49-65 ◽  
Author(s):  
K. C. Wang
Keyword(s):  
Boundary Layer ◽  
Skin Friction ◽  
Blunt Body ◽  
Three Dimensional ◽  
Prolate Spheroid ◽  
Three Dimensions ◽  
General Context ◽  
Reversed Flow ◽  
Low Incidence

This paper investigates the three-dimensional laminar boundary layer over a blunt body (a prolate spheroid) at low incidence and with reversed flow. Results reflecting the general characteristics of such a problem are presented. More significant are the features relating to the circumferential flow reversal. Some of these features confirm our early hypotheses concerning the existence of a reversed region ahead of separation and the role of the zero-cfθ line in the general context of separation in three dimensions. Other features are unexpected, including the distribution of cfμ and the shape of the separation line. Here cfθ and cfμ denote, respectively, the circumferential and meridional components of the skin friction.

scholarly journals CONFORMAL MODELS OF MAGNETOHYDRODYNAMIC TURBULENCE

1996 ◽  
Vol 11 (29) ◽  
pp. 5261-5277 ◽  
Author(s):  
OMDUTH COCEAL ◽  
STEVEN THOMAS
Keyword(s):  
Three Dimensional ◽  
Approximate Solutions ◽  
Velocity Fields ◽  
Point Of View ◽  
Three Dimensions ◽  
Finite Conductivity ◽  
Magnetohydrodynamic Turbulence ◽  
Infinite Conductivity ◽  
Conformal Models

Following the previous work of Ferretti and Yang on the role of magnetic fields in the theory of conformal turbulence, we show that nonunitary minimal model solutions to two-dimensional magnetohydrodynamics (MHD) obtained by dimensional reduction from three dimensions exist under different (and more restrictive) conditions. From a three-dimensional point of view, these conditions are equivalent to perpendicular flow, in which the magnetic and velocity fields are orthogonal. We extend the analysis to the finite conductivity case and present some approximate solutions, whose connection with the exact ones of the infinite conductivity case is also discussed.

Role of division algebra in seven-dimensional gauge theory

2015 ◽  
Vol 30 (10) ◽  
pp. 1550047
Author(s):  
Pushpa Kalauni ◽  
J. C. A. Barata
Keyword(s):  
Gauge Theory ◽  
Division Algebra ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional Vector ◽  
Vector Product ◽  
Yang Mills ◽  
Rotational Transformation

The algebra of octonions 𝕆 forms the largest normed division algebra over the real numbers ℝ, complex numbers ℂ and quaternions ℍ. The usual three-dimensional vector product is given by quaternions, while octonions produce seven-dimensional vector product. Thus, octonionic algebra is closely related to the seven-dimensional algebra, therefore one can extend generalization of rotations in three dimensions to seven dimensions using octonions. An explicit algebraic description of octonions has been given to describe rotational transformation in seven-dimensional space. We have also constructed a gauge theory based on non-associative algebra to discuss Yang–Mills theory and field equation in seven-dimensional space.

Analytic spinor fields

1969 ◽  
Vol 313 (1515) ◽  
pp. 491-507 ◽  
Keyword(s):  
Time Derivative ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Variable Theory ◽  
Complex Variable Theory ◽  
Spinor Fields ◽  
Dimensional Distribution ◽  
Linear Differential ◽  
Zero Time

An analogue of complex variable theory in the plane is obtained by considering a three-dimensional distribution of basic spinors. These satisfy the invariant linear differential equation denoted by curl W = 0, which plays the rôle of the Cauchy-Riemann equations. Spinor harmonics and associated spinor harmonics are evaluated. The analogues of Taylor series and Laurent series are obtained. Analytic continuation is discussed, and this leads to the analogue of a Riemann surface in three dimensions. These spinor fields are equivalent to the space-time spinor fields which describe elementary particles, the case considered here corresponding to zero time derivative.

scholarly journals Communicating in Three Dimensions

2019 ◽  
Vol 3 (1) ◽  
pp. 100-116
Author(s):  
Adam Rabinowitz
Keyword(s):  
Three Dimensional ◽  
3D Models ◽  
Three Dimensions ◽  
Scientific Models ◽  
Additional Information ◽  
Public Consumption ◽  
3D Documentation ◽  
New Research

After excavating the Praedia of Iulia Felix at Pompeii in 1755, architect Karl Weber published the building with an axionometric illustration that showed the remains in three-dimensional perspective. In doing so, Weber communicated additional information about the form of the building in a manner that was both visually accessible to a lay audience and sufficiently “scientific” for a scholarly one. By contrast, digital 3D documentation methods in current archaeological practice can reinforce a division between “scientific” models intended for internal consumption by the project that produces them, and external communication in the form of lower-quality online digital displays. Using recent fieldwork at the Greek colonial site of Histria in Romania as a case-study, this paper explores the space between high-resolution contextualized 3D documentation used only by an internal audience and down-scaled, decontextualized 3D content designed for public consumption. In particular, it explores whether measurable 3D models derived from photogrammetrical capture are useful in communicating excavation results to non-specialists – and if so, in what ways. It presents several scenarios for the role of high-quality 3D documentation in both formal and informal scholarly communication, and discusses the potential for the reuse of such documentation to answer new research questions.

scholarly journals On the influence of small chemical changes upon the supramolecular association in substituted 2-(phenoxy)-1,4-naphthoquinones

2019 ◽  
Vol 234 (3) ◽  
pp. 183-200
Author(s):  
Marlon D.L. Tonin ◽  
Simon J. Garden ◽  
Mukesh M. Jotani ◽  
James L. Wardell ◽  
Edward R.T. Tiekink
Keyword(s):  
Three Dimensional ◽  
Ring System ◽  
Molecular Packing ◽  
Three Dimensions ◽  
Π Interactions ◽  
X Ray Crystallography ◽  
The Common ◽  
Layer Region ◽  
Small Chemical

Abstract X-ray crystallography reveals the common feature of the title compounds is a 1,4-naphthoquinone ring system with a substituted phenoxy residue adjacent to an oxo-group to give 1 (H), 2 (3-Br), 3 (3-CF3), 4 (4-CN) and 5 (4-NO2). To a first approximation the fused ring system along with the two oxo substituents is planar with the major difference between the molecules relating to the relative orientations of the pendant phenoxy residues: dihedral angles range from 56.56(4)° (3) to 87.52(10)° (2). The presence of intermolecular C–H···O interactions is the common feature of the supramolecular association in the crystals of 1–5. In each of 1 and 5, these extend in three-dimensions but, only to supramolecular dimers in 4, chains in 2 and layers in 3. Each crystal also features C=O···π interactions, pointing to the importance of these points of contact in this series di-oxocompounds. In 2, these, along with C–Br···π interactions lead to a three-dimensional architecture. For 3, the C=O···π and π···π interactions occur within the layers which stack without directional interactions between them. In 4, C–H···O and C=O···π interactions combine to give a supramolecular layer, which also stack without directional interactions in the inter-layer region. Further analysis of the molecular packing was conducted by a Hirshfeld surface analysis (HSA). This points to the significant role of H···H, C···H/H···C and O···H/H···O contacts in the packing of 1. Notably different roles for these contacts are found in the other crystals correlating with the participation of the respective substituents in the molecular packing. The HSA suggests the association between layers in 3 (weak F···F and H···F interactions) and 4 (weak H···N interactions) is contributed by the phenoxy-substituents.

scholarly journals Changes in the three-dimensional microscale topography of human skin with aging impact its mechanical and tribological behavior

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0241533
Author(s):  
Juan G. Diosa ◽  
Ricardo Moreno ◽  
Edwin L. Chica ◽  
Junes A. Villarraga ◽  
Adrian B. Tepole
Keyword(s):  
Mechanical Behavior ◽  
Human Skin ◽  
Tribological Behavior ◽  
Complex Structure ◽  
Three Dimensional ◽  
Indentation Test ◽  
Three Dimensions ◽  
Tangential Forces ◽  
Geometric Changes

Human skin enables interaction with diverse materials every day and at all times. The ability to grasp objects, feel textures, and perceive the environment depends on the mechanical behavior, complex structure, and microscale topography of human skin. At the same time, abrasive interactions, such as sometimes occur with prostheses or textiles, can damage the skin and impair its function. Previous theoretical and computational efforts have shown that skin’s surface topography or microrelief is crucial for its tribological behavior. However, current understanding is limited to adult surface profiles and simplified two-dimensional simulations. Yet, the skin has a rich set of features in three dimensions, and the geometry of skin is known to change with aging. Here we create a numerical model of a dynamic indentation test to elucidate the effect of changes in microscale topography with aging on the skin’s response under indentation and sliding contact with a spherical indenter. We create three different microrelief geometries representative of different ages based on experimental reports from the literature. We perform the indentation and sliding steps, and calculate the normal and tangential forces on the indenter as it moves in three distinct directions based on the characteristic skin lines. The model also evaluates the effect of varying the material parameters. Our results show that the microscale topography of the skin in three dimensions, together with the mechanical behavior of the skin layers, lead to distinctive trends on the stress and strain distribution. The major finding is the increasing role of anisotropy which emerges from the geometric changes seen with aging.

scholarly journals Odor source localization in complex visual environments by fruit flies

2017 ◽  
Author(s):  
Nitesh Saxena ◽  
Dinesh Natesan ◽  
Sanjay P. Sane
Keyword(s):  
Fruit Flies ◽  
Odor Source ◽  
High Contrast ◽  
Visual Landmarks ◽  
Visual Objects ◽  
Flying Insects ◽  
Air Stream ◽  
Odor Plumes ◽  
Odor Tracking ◽  
Tracking Behavior

AbstractFlying insects routinely forage in complex and cluttered sensory environments. Their search for a food or a pheromone source typically begins with a whiff of odor, which triggers a flight response, eventually bringing the insect in the vicinity of the odor source. The precise localization of an odor source, however, requires the use of both visual and olfactory modalities, aided by air currents that trap odor molecules into turbulent plumes, which the insects track. Here, we investigated odor tracking behavior in fruit flies (Drosophila melanogaster) presented with low- or high-contrast visual landmarks, which were either paired with or separate from an attractive odor cue. These experiments were conducted either in a gentle air stream which generated odor plumes, or in still air in which odor dissipates uniformly in all directions. The trajectories of the flies revealed several novel features of their odor-tracking behavior in addition to those that have been previously documented (e.g. cast- and-surge maneuvers). First, in both moving and still air, odor-seeking flies rely on the co-occurrence of visual landmarks with olfactory cues to guide them to putative odorant objects in the decisive phase before landing. Second, flies abruptly decelerate when they encounter an odor plume, and thereafter steer towards nearby visual objects that had no inherent salience in the absence of odor. This indicates that the interception of an attractive odor increases their salience to nearby high-contrast visual landmarks. Third, flies adopt distinct odor tracking strategies during flight in moving vs. still air. Whereas they weave in and out of plumes towards an odor source when airflow is present, their approach is more gradual and incremental in still air. Both strategies are robust and flexible, and can ensure that the flies reliably find the odor source under diverse visual and airflow environments. Our experiments also indicate the possibility of an olfactory “ working memory” that enables flies to continue their search even when the olfactory feedback is reduced or absent. Together, these results provide insights into how flies determine the precise location of an odor source.

Three-Dimensional Adjustment of Terrestrial Geodetic Networks

1972 ◽  
Vol 26 (4) ◽  
pp. 397-427 ◽  
Author(s):  
D. M. J. Fubara
Keyword(s):  
Field Data ◽  
Statistical Tests ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Coordinate Systems ◽  
Geodetic Networks ◽  
Least Squares Adjustment ◽  
Data Requirements ◽  
Real Network Data

This paper shows how terrestrial geodetic networks can be rigorously adjusted in three dimensions. It summarizes investigations about the types of field data and how many of each type are necessary for the adjustment, the role of coordinate systems used, the mathematical models and which methods of least squares adjustment are desirable, and the attainable accuracies of adjusted parameters for chosen precisions of field observations. The trends for optimum design and minimum field data requirements for successful terrestrial three-dimensional adjustment are indicated. The conclusions relied on extensive use of statistical tests. Both simulated and real network data were used.

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