scholarly journals Conserved behavioral circuits govern high-speed decision-making in wild fish shoals

2018 ◽  
Vol 115 (48) ◽  
pp. 12224-12228 ◽  
Author(s):  
Andrew M. Hein ◽  
Michael A. Gil ◽  
Colin R. Twomey ◽  
Iain D. Couzin ◽  
Simon A. Levin
Keyword(s):  
Decision Making ◽  
High Speed ◽  
Neural Circuits ◽  
Decision Rules ◽  
Wild Fish ◽  
Automated System ◽  
Freely Moving ◽  
Evasion Behavior ◽  
Escape Decision

To evade their predators, animals must quickly detect potential threats, gauge risk, and mount a response. Putative neural circuits responsible for these tasks have been isolated in laboratory studies. However, it is unclear whether and how these circuits combine to generate the flexible, dynamic sequences of evasion behavior exhibited by wild, freely moving animals. Here, we report that evasion behavior of wild fish on a coral reef is generated through a sequence of well-defined decision rules that convert visual sensory input into behavioral actions. Using an automated system to present visual threat stimuli to fish in situ, we show that individuals initiate escape maneuvers in response to the perceived size and expansion rate of an oncoming threat using a decision rule that matches dynamics of known loom-sensitive neural circuits. After initiating an evasion maneuver, fish adjust their trajectories using a control rule based on visual feedback to steer away from the threat and toward shelter. These decision rules accurately describe evasion behavior of fish from phylogenetically distant families, illustrating the conserved nature of escape decision-making. Our results reveal how the flexible behavioral responses required for survival can emerge from relatively simple, conserved decision-making mechanisms.

Sex and refuge distance influence escape decision in a Liolaemus lizard when it is approached by a terrestrial predator

Behaviour ◽  
2019 ◽  
Vol 156 (9) ◽  
pp. 909-925 ◽  
Author(s):  
Carla A. Salido ◽  
Natalin S. Vicente
Keyword(s):  
Decision Making ◽  
High Speed ◽  
Sexual Dichromatism ◽  
Flight Initiation Distance ◽  
Sex Influence ◽  
Terrestrial Predator ◽  
Microclimatic Conditions ◽  
Escape Decision ◽  
Escape Speed ◽  
Flight Initiation

Abstract The decision of when and how to escape result crucial for animals because it can result in an interruption to contribute to their fitness. In the present study, we analysed whether speed attack, sex and type of refuge influenced the flight initiation distance (FID) and the closest refuge distance (CRD) in Liolaemus pacha lizards. We also compared the use of different type of refuges. Sex influence both CRD and FID, which would be discussed according to the size of their home range, the escape speed and sexual dichromatism. The interaction between speed and type of refuge used, influence CRD, suggesting that lizards perceived different predation risks. At high-speed approaches, lizards chose the closest refuge, rocks; while at low-speed approaches, lizards chose shrubs as a refuge, mainly the small ones. Lizard’s decision-making is discussed in relation to the refuge protection, their microclimatic conditions and visibility.

An atomic-resolution microscope study of Al contracts on GaAs

1986 ◽  
Vol 44 ◽  
pp. 726-727
Author(s):  
Z. Liliental-Weber ◽  
C. Nelson ◽  
R. Ludeke ◽  
R. Gronsky ◽  
J. Washburn
Keyword(s):  
High Speed ◽  
Schottky Contacts ◽  
Detailed Knowledge ◽  
The Past ◽  
Semiconductor Interfaces ◽  
Deposited Metal ◽  
Microwave Applications ◽  
Free Interfaces ◽  
Potential Use

The properties of metal/semiconductor interfaces have received considerable attention over the past few years, and the Al/GaAs system is of special interest because of its potential use in high-speed logic integrated optics, and microwave applications. For such materials a detailed knowledge of the geometric and electronic structure of the interface is fundamental to an understanding of the electrical properties of the contact. It is well known that the properties of Schottky contacts are established within a few atomic layers of the deposited metal. Therefore surface contamination can play a significant role. A method for fabricating contamination-free interfaces is absolutely necessary for reproducible properties, and molecularbeam epitaxy (MBE) offers such advantages for in-situ metal deposition under UHV conditions

scholarly journals Spatially Resolved Experimental Modal Analysis on High-Speed Composite Rotors Using a Non-Contact, Non-Rotating Sensor

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4705
Author(s):  
Julian Lich ◽  
Tino Wollmann ◽  
Angelos Filippatos ◽  
Maik Gude ◽  
Juergen Czarske ◽  
...  
Keyword(s):  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Fiber Reinforced ◽  
Structural Dynamic ◽  
Spatially Resolved ◽  
Glass Fiber Reinforced ◽  
Vibration Responses ◽  
And Performance

Due to their lightweight properties, fiber-reinforced composites are well suited for large and fast rotating structures, such as fan blades in turbomachines. To investigate rotor safety and performance, in situ measurements of the structural dynamic behaviour must be performed during rotating conditions. An approach to measuring spatially resolved vibration responses of a rotating structure with a non-contact, non-rotating sensor is investigated here. The resulting spectra can be assigned to specific locations on the structure and have similar properties to the spectra measured with co-rotating sensors, such as strain gauges. The sampling frequency is increased by performing consecutive measurements with a constant excitation function and varying time delays. The method allows for a paradigm shift to unambiguous identification of natural frequencies and mode shapes with arbitrary rotor shapes and excitation functions without the need for co-rotating sensors. Deflection measurements on a glass fiber-reinforced polymer disk were performed with a diffraction grating-based sensor system at 40 measurement points with an uncertainty below 15 μrad and a commercial triangulation sensor at 200 measurement points at surface speeds up to 300 m/s. A rotation-induced increase of two natural frequencies was measured, and their mode shapes were derived at the corresponding rotational speeds. A strain gauge was used for validation.

Enhanced Grain Refinement of W18Cr4V High‐Speed Steel using in situ TiN‐Nb‐Cr@Graphene/Fe Nanocomposite Inoculant

2021 ◽  
Author(s):  
Lina Bai ◽  
Chunxiang Cui ◽  
Jianjun Zhang ◽  
Lichen Zhao ◽  
Guixing Zheng ◽  
...  
Keyword(s):  
Grain Refinement ◽  
High Speed ◽  
High Speed Steel

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

Naturalistic Decision Making in High Performance Team Sport Coaching

2015 ◽  
Vol 2 (2) ◽  
pp. 152-168 ◽  
Author(s):  
Stephen Harvey ◽  
John William Baird Lyle ◽  
Bob Muir
Keyword(s):  
Decision Making ◽  
High Performance ◽  
Recent Literature ◽  
Critical Factors ◽  
Naturalistic Decision Making ◽  
Problem Framing ◽  
Stimulated Recall ◽  
Suitable Framework ◽  
And Training

A defining element of coaching expertise is characterised by the coach’s ability to make decisions. Recent literature has explored the potential of Naturalistic Decision Making (NDM) as a useful framework for research into coaches’ in situ decision making behaviour. The purpose of this paper was to investigate whether the NDM paradigm offered a valid mechanism for exploring three high performance coaches’ decision-making behaviour in competition and training settings. The approach comprised three phases: 1) existing literature was synthesised to develop a conceptual framework of decision-making cues to guide and shape the exploration of empirical data; 2) data were generated from stimulated recall procedures to populate the framework; 3) existing theory was combined with empirical evidence to generate a set of concepts that offer explanations for the coaches’ decision-making behaviour. Findings revealed that NDM offered a suitable framework to apply to coaches’ decision-making behaviour. This behaviour was guided by the emergence of a slow, interactive script that evolves through a process of pattern recognition and/or problem framing. This revealed ‘key attractors’ that formed the initial catalyst and the potential necessity for the coach to make a decision through the breaching of a ‘threshold’. These were the critical factors for coaches’ interventions.

In Situ Observation Method for Quantitative Evaluation of Solidification Phenomena and Solidification Cracks during Welding

2014 ◽  
Vol 782 ◽  
pp. 3-7
Author(s):  
Kenji Shinozaki ◽  
Motomichi Yamamoto ◽  
Kohta Kadoi ◽  
Peng Wen
Keyword(s):  
High Speed ◽  
Video Camera ◽  
Solidification Cracking ◽  
In Situ Observation ◽  
High Speed Video Camera ◽  
Varestraint Test ◽  
Solidification Cracks ◽  
Observation Method ◽  
Solidification Crack

Solidification cracking during welding is very serious problem for practical use. Therefore, there are so many reports concerning solidification cracking. Normally, solidification cracking susceptibility of material is quantitatively evaluated using Trans-Varestraint test. On the other hand, local solidification cracking strain was tried to measure precisely using in-situ observation method, called MISO method about 30 years ago. Recently, digital high-speed video camera develops very fast and its image quality is very high. Therefore, we have started to observe solidification crack using in site observation method. In this paper, the local critical strain of a solidification crack was measured and the high temperature ductility curves of weld metals having different dilution ratios and different grain sizes to evaluate quantitatively the effects of dilution ratio and grain size on solidification cracking susceptibility by using an improved in situ observation method.

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