scholarly journals Head stabilization in small vertebrates that run at high frequencies with a sprawled posture

2020 ◽  
Vol 130 (1) ◽  
pp. 195-204
Author(s):  
Cas Jorissen ◽  
Eric Paillet ◽  
Jan Scholliers ◽  
Peter Aerts ◽  
Jana Goyens
Keyword(s):  
Sense Of Self ◽  
Head Movements ◽  
Phase Lag ◽  
Small Animals ◽  
Spatial Awareness ◽  
Head Stabilization ◽  
High Frequencies ◽  
Stabilization Control ◽  
Vestibular Perception ◽  
Set Up

Abstract Small animals face a large challenge when running. A stable head is key to maintenance of a stable gaze and a good sense of self-motion and spatial awareness. However, trunk undulations caused by the cyclic limb movements result in involuntary head movements. Hence, the head needs to be stabilized. Humans are capable of stabilizing their head up to 2–3 Hz, but small animals run at cycle frequencies that are up to six times higher. We wondered how natural selection has adapted their head stabilization control. We observed that the relative contributions of vision, on the one hand, and vestibular perception and proprioception, on the other hand, remain the same when lizards undergo fast or slow body undulations in an experimental set-up. Lizards also maintain a short phase lag at both low and high undulation frequencies. Hence, we found no indication that they use a different control mechanism at high frequencies. Instead, head stabilization probably remains possible owing to faster reflex pathways and a lower head inertia. Hence, the intrinsic physical and neurological characteristics of lizards seem to be sufficient to enable head stabilization at high frequencies, obviating the need for evolutionary adaptation of the control pathways. These properties are not unique to lizards and might, therefore, also facilitate head stabilization at high frequencies in other small, fast animals.

scholarly journals How to set up a postmortem facility in a farm animal practice

Livestock ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 196-201
Author(s):  
John F Mee ◽  
Rhona Ley
Keyword(s):  
General Practice ◽  
General Practitioners ◽  
Diagnostic Tool ◽  
Small Ruminants ◽  
Farm Animal ◽  
Small Animals ◽  
Animal Medicine ◽  
Set Up ◽  
Postmortem Examinations

Postmortem examinations can be a useful diagnostic tool in farm animal medicine; however, they are often avoided in general practice because of a lack of appropriate facilities and expertise/familiarity with techniques. This article describes the setting up of a basic facility to allow general practitioners to perform postmortem examinations of calves, small ruminants and other small animals, e.g. poultry.

scholarly journals A System-Agnostic, Adaptable and Extensible Animal Support Cradle System for Cardio-Respiratory-Synchronised, and Other, Multi-Modal Imaging of Small Animals

Tomography ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 39-54
Author(s):  
Veerle Kersemans ◽  
Stuart Gilchrist ◽  
Philip Danny Allen ◽  
Sheena Wallington ◽  
Paul Kinchesh ◽  
...  
Keyword(s):  
Scientific Data ◽  
Cardiac Monitoring ◽  
Small Animals ◽  
Maintenance System ◽  
Wide Range ◽  
Set Up ◽  
Animal Handling ◽  
Imaging Performance ◽  
Significant Effort

Standardisation of animal handling procedures for a wide range of preclinical imaging scanners will improve imaging performance and reproducibility of scientific data. Whilst there has been significant effort in defining how well scanners should operate and how in vivo experimentation should be practised, there is little detail on how to achieve optimal scanner performance with best practices in animal welfare. Here, we describe a system-agnostic, adaptable and extensible animal support cradle system for cardio-respiratory-synchronised, and other, multi-modal imaging of small animals. The animal support cradle can be adapted on a per application basis and features integrated tubing for anaesthetic and tracer delivery, an electrically driven rectal temperature maintenance system and respiratory and cardiac monitoring. Through a combination of careful material and device selection, we have described an approach that allows animals to be transferred whilst under general anaesthesia between any of the tomographic scanners we currently or have previously operated. The set-up is minimally invasive, cheap and easy to implement and for multi-modal, multi-vendor imaging of small animals.

A case study using narrative therapy to “rewrite” the non-conforming reputation of a high school student

2001 ◽  
Vol 11 ◽  
pp. 131-140
Author(s):  
Miguel Fernandez
Keyword(s):  
High School ◽  
Narrative Therapy ◽  
Sense Of Self ◽  
Male Student ◽  
School Personnel ◽  
Young Person ◽  
Negative Effects ◽  
Set Up ◽  
The One

This paper begins with a brief description of research stating that adolescents in schools generally pursue reputations that are either nonconforming or conforming. This is usually achieved through the development of goals specific to each type of reputation. Essential to the maintenance of a reputation is the recruitment of an audience. It is also proposed by researchers that intervention by school personnel becomes crucial when trying to counteract the negative effects of a nonconforming Using a case study, this paper investigates the use of Narrative Therapy with a 15-year-old male student in a high school who had developed a nonconforming reputation. A three-year-old nonconforming reputation is put through a Narrative framework that challenges “its” goals and reason for being. As the sessions progress, there is a sense that this young person is beginning to move towards a more preferred sense of self that is potentially different from the one set-up by the nonconforming reputation. This is achieved by using a Narrative style dialogical approach that shows how language censures and as well as its ability to promote (liberate) chosen behaviour. Apart from the development of a more preferred sense of self, an interesting outcome from using this approach has also been the unique way restraint works within the school.

A reexamination of the gain of the vestibuloocular reflex

1986 ◽  
Vol 56 (2) ◽  
pp. 439-450 ◽  
Author(s):  
E. Viirre ◽  
D. Tweed ◽  
K. Milner ◽  
T. Vilis
Keyword(s):  
Target Location ◽  
No Reduction ◽  
Angular Displacement ◽  
Head Rotation ◽  
Phase Lag ◽  
Vestibuloocular Reflex ◽  
High Frequencies ◽  
Axis Of Rotation ◽  
Large Gain ◽  
The Ideal

The properties of the vestibuloocular reflex (VOR) when the axis of rotation is behind the eyes and fixation of a near target is required were studied in the monkey. The magnitude of VOR gain in each eye was found to be above 1.0 and near the ideal value for stabilizing a retinal image. Evidence that this large VOR gain was not visually mediated was provided by the observations that no reduction in gain and no phase lag were observed at high frequencies of head rotation (2 Hz), large gain was observed in the dark, and large gain was observed within 10-20 ms of the start of head rotation. The magnitude of VOR gain was found to increase with increasing radius of head rotation and also to increase with decreasing target distance. When the distances from the two eyes to the target were different the instantaneous velocities and VOR gains of the eyes were also different. The dependence on radius of rotation indicates that the VOR is mediated by a combination of otolith and canal inputs. A general model for otolith-canal interaction is proposed in which VOR gain is based on a computation of target location relative to the head. This model simplifies to the classical VOR reflex when a cyclopean eye is subjected only to angular displacement.

Gas Waterhammer

2007 ◽  
Author(s):  
Hugh Goyder
Keyword(s):  
Acoustic Waves ◽  
Safety Valve ◽  
Initial Conditions ◽  
Assessment Process ◽  
High Frequencies ◽  
Lack Of Information ◽  
Process Plant ◽  
Pressure Relief Valves ◽  
Support Conditions ◽  
Set Up

Gas process plant includes pressure relief valves, or pressure safety valves, which enable vessels containing high pressure gas to be emptied quickly into a relief main which takes the gas to a flair stack. The pressure safety valve opens suddenly and sets up acoustic waves, in the manner of a waterhammer, that propagate backwards and forwards in pipework until a steady flow is obtained. Such acoustic waves may set up large forces in pipework that may cause damage. Consequently, an assessment process is required that includes the forces generated by the gas and the resultant stresses in the pipework. One particular problem, investigated here, is the initial conditions for the acoustic waves as the pressure safety valve lifts. The main difficulty with an assessment is the near impossibility of modelling the pipe dynamics adequately. This difficulty is due to the lack of information available concerning pipework support systems and the need to model pipework vibration to high frequencies. A conservative method for assessment based on looking at extremes of support conditions is proposed.

Experimental Set-up for FLASH Proton Irradiation of Small Animals Using a Clinical System

2018 ◽  
Vol 102 (3) ◽  
pp. 619-626 ◽  
Author(s):  
Annalisa Patriarca ◽  
Charles Fouillade ◽  
Michel Auger ◽  
Frédéric Martin ◽  
Frédéric Pouzoulet ◽  
...  
Keyword(s):  
Proton Irradiation ◽  
Small Animals ◽  
Set Up

Vestibular Gaze Stabilization: Different Behavioral Strategies for Arboreal and Terrestrial Avians

2005 ◽  
Vol 93 (3) ◽  
pp. 1165-1173 ◽  
Author(s):  
Asim Haque ◽  
J. David Dickman
Keyword(s):  
Avian Species ◽  
Head Movements ◽  
Head Motion ◽  
Behavioral Strategies ◽  
Specific Behavior ◽  
Gaze Stabilization ◽  
High Frequencies ◽  
Gaze Stability ◽  
Species Specific

In birds, it is thought that head movements play a major role in the reflexive stabilization of gaze and vision. In this study, we investigated the contributions of the eye and head to gaze stabilization during rotations under both head-fixed [vestibuloocular (VOR)] and head-free conditions in two avian species: pigeons and quails. These two species differ both in ocular anatomy (the pigeon has 2 distinct foveal regions), as well as in behavioral repertoires. Pigeons are arboreal, fly extended distances, and can navigate. Quails are primarily engrossed in terrestrial niches and fly only short distances. Unlike the head-fixed VOR gains that were under-compensatory for both species, gaze gains under head-free conditions were completely compensatory at high frequencies. This compensation was achieved primarily with head movements in pigeons, but with combined head and eye-in-head contributions in the quail. In contrast, eye-in-head motion, which was significantly reduced for head-free compared with head-fixed conditions, contributed very little to overall gaze stability in pigeons. These results suggest that disparity between the stabilization strategies employed by these two birds may be attributed to differences in species-specific behavior and anatomy.

Fast integrated flow plethysmograph for small mammals

1981 ◽  
Vol 50 (5) ◽  
pp. 1104-1110 ◽  
Author(s):  
E. E. Sinnett ◽  
A. C. Jackson ◽  
D. E. Leith ◽  
J. P. Butler
Keyword(s):  
Vital Capacity ◽  
Phase Lag ◽  
Order Flow ◽  
Zeroth Order ◽  
Amplitude Response ◽  
High Frequencies ◽  
First Order ◽  
Response Characteristics ◽  
Flow Type ◽  
Reference Flow

The accurate measurement of a forced vital capacity (FVC) maneuver in a small mammal requires that the plethysmograph in use have good response characteristics at high frequencies. We develop, on a theoretical basis, the behavior of zeroth-order (pressure type), first-order (flow type without inertance), and second-order (flow type with inertance) plethysmogrphs. The actual frequency response of a mouse-sized plethysmograph is then presented, and a technique for improving its response characteristics is described. A flat amplitude response (within 3% of a reference flow taken as truth) was obtained for sinusoidal inputs below 240 Hz. A phase lag with respect to the reference flow equivalent to a simple time delay of 1.4 ms was observed up to 150 Hz. A typical FVC curve for a mouse is shown, and criteria are provided for designing similar plethysmographs suitable for use with larger animals.

Depth on a Flat Screen

1987 ◽  
Vol 64 (3_suppl) ◽  
pp. 1023-1034 ◽  
Author(s):  
G. J. F. Smets ◽  
C. J. Overbeeke ◽  
M. H. Stratmann
Keyword(s):  
Real Life ◽  
Depth Estimation ◽  
Head Movements ◽  
Monocular Vision ◽  
Passive Condition ◽  
Monitor Screen ◽  
Flat Screen ◽  
Active Condition ◽  
Set Up ◽  
Maximum Reliability

The hypothesis was tested that the coupling of parallax shifts between objects depicted on a monitor screen around a fixation point with the head movements of an observer viewing this screen monocularly around a point coinciding with the fixation point is sufficient to create a convincing depth impression and to enable the observer to make reliable estimations of depth. The estimates were based on monocular vision and involved the aligning of wedges. The investigation consisted of two analogous experiments carried out simultaneously, one on depth estimations virtually in the screen and one on depth estimations virtually in front of the screen. In each experiment three conditions were compared: an active condition in which the coupling of parallax shifts and observer's head movements operated, a passive condition in which it did not, and a real-life set-up to measure the maximum reliability in depth estimation. The hypothesis is confirmed: in the active condition the variances in the alignments are significantly smaller than in the passive condition and approach those in the real-life set-up. This holds not only for estimates in the screen but also for estimates in front of the screen, that is, we can make a thing apparently leap out of the screen towards the observer. Results are interpreted against the background of the debate between the direct and the indirect theories of perception.

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