THE ORIENTATION OF HORSE FLIES AND DEER FLIES (TABANIDAE:DIPTERA): II. THE ROLE OF SOME VISUAL FACTORS IN THE ATTRACTIVENESS OF DECOY SILHOUETTES

1962 ◽  
Vol 40 (5) ◽  
pp. 685-695 ◽  
Author(s):  
G. K. Bracken ◽  
Wm. Hanec ◽  
A. J. Thorsteinson
Keyword(s):  
Three Dimensional ◽  
Vertical Plane ◽  
The Other ◽  
Two Dimensional ◽  
Horse Flies ◽  
Convex Curvature

The attractiveness of colored spheres was compared in the field for several tabanid species. Black and red spheres were highly attractive to all the species. Tabanus illotus was attracted nearly equally to black, gray, and white silhouettes. The attractiveness of gray and white spheres for the other species decreased rapidly with increasing reflectance. Green and yellow spheres were unattractive for all species. Two-dimensional black silhouettes attracted only a small number of tabanids. Three-dimensional black silhouettes with plane surfaces attracted larger numbers of flies. Glossy black silhouettes with convex curvature in the vertical plane were much more attractive than other silhouettes. Interpretations of these results are presented.

Three-Dimensional Reconstruction of Two Forms of the Chaperonin GRO EL

1990 ◽  
Vol 48 (1) ◽  
pp. 258-259
Author(s):  
J.L. Carrascosa ◽  
G. Abella ◽  
S. Marco ◽  
M. Muyal ◽  
J.M. Carazo
Keyword(s):  
Three Dimensional ◽  
The Other ◽  
Two Dimensional ◽  
Series Method ◽  
Three Dimensional Reconstruction ◽  
Structural Components ◽  
E Coli ◽  
Dimensional Reconstruction ◽  
Morphogenetic Factors ◽  
Tilt Series

Chaperonins are a class of proteins characterized by their role as morphogenetic factors. They trantsiently interact with the structural components of certain biological aggregates (viruses, enzymes etc), promoting their correct folding, assembly and, eventually transport. The groEL factor from E. coli is a conspicuous member of the chaperonins, as it promotes the assembly and morphogenesis of bacterial oligomers and/viral structures.We have studied groEL-like factors from two different bacteria:E. coli and B.subtilis. These factors share common morphological features , showing two different views: one is 6-fold, while the other shows 7 morphological units. There is also a correlation between the presence of a dominant 6-fold view and the fact of both bacteria been grown at low temperature (32°C), while the 7-fold is the main view at higher temperatures (42°C). As the two-dimensional projections of groEL were difficult to interprete, we studied their three-dimensional reconstruction by the random conical tilt series method from negatively stained particles.

scholarly journals On the Kirchhoff-Love Hypothesis (Revised and Vindicated)

2021 ◽  
Author(s):  
Olivier Ozenda ◽  
Epifanio G. Virga
Keyword(s):  
Free Energy ◽  
Dimension Reduction ◽  
Three Dimensional ◽  
Energy Functional ◽  
The Other ◽  
Variational Model ◽  
Two Dimensional ◽  
Elastic Plates ◽  
Kinematic Constraint ◽  
Free Energy Functional

AbstractThe Kirchhoff-Love hypothesis expresses a kinematic constraint that is assumed to be valid for the deformations of a three-dimensional body when one of its dimensions is much smaller than the other two, as is the case for plates. This hypothesis has a long history checkered with the vicissitudes of life: even its paternity has been questioned, and recent rigorous dimension-reduction tools (based on standard $\varGamma $ Γ -convergence) have proven to be incompatible with it. We find that an appropriately revised version of the Kirchhoff-Love hypothesis is a valuable means to derive a two-dimensional variational model for elastic plates from a three-dimensional nonlinear free-energy functional. The bending energies thus obtained for a number of materials also show to contain measures of stretching of the plate’s mid surface (alongside the expected measures of bending). The incompatibility with standard $\varGamma $ Γ -convergence also appears to be removed in the cases where contact with that method and ours can be made.

Sight distance red zones on combined horizontal and sag vertical curves

1998 ◽  
Vol 25 (4) ◽  
pp. 621-630 ◽  
Author(s):  
Yasser Hassan ◽  
Said M Easa
Keyword(s):  
Quantitative Analysis ◽  
Three Dimensional ◽  
The Other ◽  
Two Dimensional ◽  
Horizontal Curve ◽  
Sight Distance ◽  
Stopping Sight Distance ◽  
Three Dimensional Models ◽  
Highway Alignment ◽  
Current Standards

Coordination of highway horizontal and vertical alignments is based on subjective guidelines in current standards. This paper presents a quantitative analysis of coordinating horizontal and sag vertical curves that are designed using two-dimensional standards. The locations where a horizontal curve should not be positioned relative to a sag vertical curve (called red zones) are identified. In the red zone, the available sight distance (computed using three-dimensional models) is less than the required sight distance. Two types of red zones, based on stopping sight distance (SSD) and preview sight distance (PVSD), are examined. The SSD red zone corresponds to the locations where an overlap between a horizontal curve and a sag vertical curve should be avoided because the three-dimensional sight distance will be less than the required SSD. The PVSD red zone corresponds to the locations where a horizontal curve should not start because drivers will not be able to perceive it and safely react to it. The SSD red zones exist for practical highway alignment parameters, and therefore designers should check the alignments for potential SSD red zones. The range of SSD red zones was found to depend on the different alignment parameters, especially the superelevation rate. On the other hand, the results showed that the PVSD red zones exist only for large values of the required PVSD, and therefore this type of red zones is not critical. This paper should be of particular interest to the highway designers and professionals concerned with highway safety.Key words: sight distance, red zone, combined alignment.

scholarly journals A Possible Three-Dimensional Mechanism for Oscillating Wobbles in Tropical Cyclone–Like Vortices with Concentric Eyewalls

2018 ◽  
Vol 75 (7) ◽  
pp. 2157-2174 ◽  
Author(s):  
Konstantinos Menelaou ◽  
M. K. Yau ◽  
Tsz-Kin Lai
Keyword(s):  
Tropical Cyclone ◽  
Nonlinear Model ◽  
Three Dimensional ◽  
The Other ◽  
Sensitivity Analyses ◽  
Two Dimensional ◽  
Triggering Mechanism ◽  
Eigenmode Analysis ◽  
Concentric Eyewalls ◽  
Third Dimension

Abstract It is known that concentric eyewalls can influence tropical cyclone (TC) intensity. However, they can also influence TC track. Observations indicate that TCs with concentric eyewalls are often accompanied by wobbling of the inner eyewall, a motion that gives rise to cycloidal tracks. Currently, there is no general consensus of what might constitute the dominant triggering mechanism of these wobbles. In this paper we revisit the fundamentals. The control case constitutes a TC with symmetric concentric eyewalls embedded in a quiescent environment. Two sets of experiments are conducted: one using a two-dimensional nondivergent nonlinear model and the other using a three-dimensional nonlinear model. It is found that when the system is two-dimensional, no wobbling of the inner eyewall is triggered. On the other hand, when the third dimension is introduced, an amplifying wobble is evident. This result contradicts the previous suggestion that wobbles occur only in asymmetric concentric eyewalls. It also contradicts the suggestion that environmental wind shear can be the main trigger. Examination of the dynamics along with complementary linear eigenmode analysis revealed the triggering mechanism to be the excitation of a three-dimensional exponentially growing azimuthal wavenumber-1 instability. This instability is induced by the coupling of two baroclinic vortex Rossby waves across the moat region. Additional sensitivity analyses involving reasonable modifications to vortex shape parameters, perturbation vertical length scale, and Rossby number reveal that this instability can be systematically the most excited. The growth rates are shown to peak for perturbations characterized by realistic vertical length scales, suggesting that this mechanism can be potentially relevant to actual TCs.

3D Structure of Striations in the North Pacific

2021 ◽  
Author(s):  
YU ZHANG ◽  
YU PING GUAN ◽  
RUI XIN HUANG
Keyword(s):  
North Pacific ◽  
3D Structure ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Dimensional Structure ◽  
The North ◽  
Layer Analysis ◽  
Fluid Potential ◽  
The North Pacific

AbstractOcean striations are composed of alternating quasi-zonal band-like flows; this kind of organized structure of currents be found in all world’s oceans and seas. Previous studies have mainly been focused on the mechanisms of their generation and propagation. This study uses the spatial high-pass filtering to obtain the three-dimensional structure of ocean striations in the North Pacific in both the z-coordinate and σ-coordinate based on 10-yr averaged SODA3 data. First, we identify an ideal-fluid potential density domain where the striations are undisturbed by the surface forcing and boundary effects. Second, using the isopycnal layer analysis, we show that on isopycnal surfaces the orientations of striations nearly follow the potential vorticity (PV) contours, while in the meridional-vertical plane the central positions of striations are generally aligned with the latitude of zero gradient of the relative PV. Our analysis provides a simple dynamical interpretation and better understanding for the role of ocean striations.

The Role of Three Dimension Computerized Imaging in Hand Surgery

1987 ◽  
Vol 12 (3) ◽  
pp. 349-352
Author(s):  
J. ENGEL ◽  
M. SALAI ◽  
B. YAFFE ◽  
R. TADMOR
Keyword(s):  
Three Dimensional ◽  
Hand Surgery ◽  
New Technique ◽  
Silicone Implants ◽  
Three Dimension ◽  
Two Dimensional ◽  
Radiological Imaging ◽  
Preliminary Results ◽  
Dimensional Picture

Three-dimensional computerized imaging is a new modality of radiological imaging. This new technique transforms the two-dimensional slices of bi-plane CT into a three-dimensional picture by a computer’s monitor adjusted to the system. This system enables the physician to rotate the angle of viewing of the desired region to any desired angle. Moreover, this system can delete certain features of different densities from the picture, such as silicone implants, thus improving visualization. Our preliminary results using this technique are presented. The advantages, pitfalls, and suggested future applications of this new technique in hand surgery are discussed.

scholarly journals Dynamo in the Presence of Differential Rotation

1976 ◽  
Vol 71 ◽  
pp. 345-351
Author(s):  
S. I. Vainshtein
Keyword(s):  
Axial Symmetry ◽  
Three Dimensional ◽  
Positive Answer ◽  
The Other ◽  
Two Dimensional ◽  
Toroidal Vortex ◽  
Complex Motion ◽  
Dynamo Theory ◽  
Density Inhomogeneity ◽  
Rotating Star

It is well know that the ‘dynamo’ theory has a number of vetoes; e.g. axisymmetric, two-dimensional, central-symmetric, etc. dynamo are impossible. In principle, the problem is essentially three-dimensional in any coordinate system. This is the main difficulty of both the theory itself and its possible applications. In fact, one prefers to believe that, for example, a non-rigid body-rotating star or convection in the Earth's nucleus possesses axis symmetry. However, due to the above vetoes one has to add finer effects (Coriolis strength, density, inhomogeneity) to create asymmetrical convection. On the other hand, the authors try to find the most simple movements with minimum deviations from axial symmetry. Thus, the Herzenberg's dynamo (Herzenberg, 1958) is realized by two rotating cylinders, axes of which are parallel to each other (see also Galaitis, 1973; Galaitis and Freinberg, 1974), the Lortz's dynamo-spiral movement (Lortz, 1968; Ponomarenko, 1973). Nevertheless, the mentioned vetoes possess a common feature, the assumption regarding the symmetry extends both to the movement and to the field. Hence, it makes sense to raise a question whether symmetric movements are able to generate an asymmetric field. A positive answer to this question, in particular, is given by Tverskoy's model (Tverskoy, 1966) – the toroidal vortex. The latter possesses axial symmetry. Nevertheless, the toroidal vortex is a complex motion; we will proceed along the path of a minimum simplification.

Role of divalent cation (Ba) substitution in the Li+ ion conductor LiTi2(PO4)3: a molecular dynamics study

2020 ◽  
Vol 22 (26) ◽  
pp. 14471-14479
Author(s):  
Kartik Sau ◽  
Tamio Ikeshoji ◽  
Supriya Roy
Keyword(s):  
Molecular Dynamics ◽  
Divalent Cation ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Ion Diffusion ◽  
Ion Conductor ◽  
Li Ion ◽  
Ba Substitution

Influence of Ba2+ ordering on cationic diffusion: (a) three-dimensional low Li+ ion diffusion using randomly substituted Ba2+, and (b) two-dimensional layered type high Li+ ion diffusion using specifically ordered substitution of Ba2+.

Poly[deca-μ2-cyanido-dicyanidobis(μ2-ethylenediamine)bis(ethylenediamine)tricadmium(II)dicobalt(III)]: a two-dimensional coordination polymer

2009 ◽  
Vol 65 (3) ◽  
pp. m118-m120
Author(s):  
Olha Sereda ◽  
Helen Stoeckli-Evans
Keyword(s):  
Coordination Polymer ◽  
Network Structure ◽  
General Position ◽  
Rotation Axis ◽  
Three Dimensional ◽  
The Other ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Asymmetric Unit ◽  
Dimensional Network

The title coordination polymer, [Cd3Co2(CN)12(C2H8N2)4]n, has an infinite two-dimensional network structure. The asymmetric unit is composed of two crystallographically independent CdIIatoms, one of which is located on a twofold rotation axis. There are two independent ethylenediamine (en) ligands, one of which bis-chelates to the Cd atom that sits in a general position, while the other bridges this Cd atom to that sitting on the twofold axis. The Cd atom located on the twofold rotation axis is linked to four equivalent CoIIIatomsviacyanide bridges, while the Cd atom that sits in a general position is connected to three equivalent CoIIIatomsviacyanide bridges. In this way, a series of trinuclear, tetranuclear and pentanuclear macrocycles are linked to form a two-dimensional network structure lying parallel to thebcplane. In the crystal structure, these two-dimensional networks are linkedviaN—H...N hydrogen bonds involving an en NH2H atom and a cyanide N atom, leading to the formation of a three-dimensional structure. This coordination polymer is only the second example involving a cyanometallate where the en ligand is present in both chelating and bridging coordination modes.

scholarly journals Phenomenal Causality and Sensory Realism

i-Perception ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 204166952092703
Author(s):  
Kristof Meding ◽  
Sebastian A. Bruijns ◽  
Bernhard Schölkopf ◽  
Philipp Berens ◽  
Felix A. Wichmann
Keyword(s):  
Visual Perception ◽  
Three Dimensional ◽  
The Other ◽  
Two Dimensional ◽  
Perception Of Causality ◽  
Phenomenal Causality ◽  
Intuitive Physics ◽  
Three Dimensional Presentation ◽  
Cue Conflict ◽  
Motion Dynamics

One of the most important tasks for humans is the attribution of causes and effects in all wakes of life. The first systematical study of visual perception of causality—often referred to as phenomenal causality—was done by Albert Michotte using his now well-known launching events paradigm. Launching events are the seeming collision and seeming transfer of movement between two objects—abstract, featureless stimuli (“objects”) in Michotte’s original experiments. Here, we study the relation between causal ratings for launching events in Michotte’s setting and launching collisions in a photorealistically computer-rendered setting. We presented launching events with differing temporal gaps, the same launching processes with photorealistic billiard balls, as well as photorealistic billiard balls with realistic motion dynamics, that is, an initial rebound of the first ball after collision and a short sliding phase of the second ball due to momentum and friction. We found that providing the normal launching stimulus with realistic visuals led to lower causal ratings, but realistic visuals together with realistic motion dynamics evoked higher ratings. Two-dimensional versus three-dimensional presentation, on the other hand, did not affect phenomenal causality. We discuss our results in terms of intuitive physics as well as cue conflict.

Sign in / Sign up

Export Citation Format

Share Document