Pigeon Homing as a Model Case of Goal-Oriented Navigation

2019 ◽  
pp. 673-684
Author(s):  
Hans G. Wallraff
Keyword(s):  
Model Case ◽  
Pigeon Homing

scholarly journals Seven theses on pigeon homing deduced from empirical findings

1996 ◽  
Vol 199 (1) ◽  
pp. 105-111 ◽  
Author(s):  
H Wallraff
Keyword(s):  
Life Histories ◽  
Time Course ◽  
Spatial Information ◽  
Temporal Distribution ◽  
Release Site ◽  
Initial Orientation ◽  
Experimental Conditions ◽  
Model Case ◽  
Pigeon Homing ◽  
The Way

Experimental findings obtained in recent years make it possible to recognize and distinguish the most relevant components determining homing flights of displaced pigeons. Conclusions deduced from these experiments, more or less compelling or tentative, are presented in the form of seven theses, supplemented by several subtheses along with reference to empirical data. The principal theses are as follows. (1) Passively displaced pigeons find the way home by using location-dependent signals and not by path integration based on recording of motion. Pigeons are able to home, even from unfamiliar areas, without access to potentially useful information during transport to the release site. (2) Home-related orientation of pigeons in unfamiliar areas requires positional information acquired olfactorily from atmospheric trace gases. Empirically deduced details of olfactory navigation are enumerated (connection with winds and the sun, inaccuracy, spatial range, time course of sampling and memorizing spatial information, etc.). The critical gap in our knowledge, i.e. the nature and spatio-temporal distribution of the substances involved, is provisionally filled by speculation. (3) In familiar areas, known from previous flights, the visual landscape is used additionally to find the way home. (4) Initial orientation of pigeons does not exclusively reflect home-related navigation but includes components independent of the position with respect to home. Observed bearings are co-determined by a general preference for a certain compass direction and by distracting features of the nearby landscape. (5) Proportions among components controlling initial orientation according to theses 2-4 are highly variable depending on local, temporal and experimental conditions and on the life histories of the pigeons. This complexity greatly restricts recognition of the navigationally relevant components of behaviour at a given release site. (6) Sensory inputs, being neither olfactory nor visual, do not substantially contribute to determining the current position with respect to home. This thesis need not be definitive, but at present no contradicting evidence is available. (7) Pigeon homing is a model case of bird homing in general. Experiments with other species support this thesis. So far, there is no reason to assume that wild birds apply mechanisms fundamentally different from those of pigeons to find the way home.

Clinical Implications of the Center of Balance for a Veteran with Traumatic Brain Injury

2015 ◽  
pp. 280-289
Keyword(s):  
Traumatic Brain Injury ◽  
Case Report ◽  
Brain Injury ◽  
Benign Paroxysmal Positional Vertigo ◽  
Medical Center ◽  
Treatment Plan ◽  
Successful Outcome ◽  
Model Case ◽  
Positional Vertigo ◽  
Paroxysmal Positional Vertigo

Background: It is known that traumatic brain injury (TBI), even of the mild variety, can cause diffuse multisystem neurological damage. Coordination of sensory input from the visual, vestibular and somatosensory pathways is important to obtain proper balance and stabilization in the visual environment. This coordination of systems is potentially disrupted in TBI leading to visual symptoms and complaints of dizziness and imbalance. The Center of Balance (COB) at the Northport Veterans Affairs Medical Center (VAMC) is an interprofessional clinic specifically designed for patients with such complaints. An evaluation entails examination by an optometrist, audiologist and physical therapist and is concluded with a comprehensive rehabilitative treatment plan. The clinical construct will be described and a case report will be presented to demonstrate this unique model. Case Report: A combat veteran with a history of a gunshot wound to the skull, blunt force head trauma and exposure to multiple explosions presented with complaints of difficulty reading and recent onset dizziness. After thorough evaluation in the COB, the patient was diagnosed with and treated for severe oculomotor dysfunction and benign paroxysmal positional vertigo. Conclusion: Vision therapy was able to provide a successful outcome via improvement of oculomotor efficiency and control. Physical therapy intervention was able to address the benign paroxysmal positional vertigo. The specific evaluation and management as pertains to the aforementioned diagnoses, as well as the importance of an interprofessional rehabilitative approach, will be outlined.

A study on appropriate investment of pipeline rehabilitation for water distribution network

2005 ◽  
Vol 5 (2) ◽  
pp. 31-38
Author(s):  
A. Asakura ◽  
A. Koizumi ◽  
O. Odanagi ◽  
H. Watanabe ◽  
T. Inakazu
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Water Supply ◽  
Water Distribution ◽  
Ad Hoc ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Optimal Basis ◽  
Model Case

In Japan most of the water distribution networks were constructed during the 1960s to 1970s. Since these pipelines were used for a long period, pipeline rehabilitation is necessary to maintain water supply. Although investment for pipeline rehabilitation has to be planned in terms of cost-effectiveness, no standard method has been established because pipelines were replaced on emergency and ad hoc basis in the past. In this paper, a method to determine the maintenance of the water supply on an optimal basis with a fixed budget for a water distribution network is proposed. Firstly, a method to quantify the benefits of pipeline rehabilitation is examined. Secondly, two models using Integer Programming and Monte Carlo simulation to maximize the benefits of pipeline rehabilitation with limited budget were considered, and they are applied to a model case and a case study. Based on these studies, it is concluded that the Monte Carlo simulation model to calculate the appropriate investment for the pipeline rehabilitation planning is both convenient and practical.

Design and Operational Analyses of Activated Sludge Processes Using Respirometrically Calibrated Models

1992 ◽  
Vol 26 (3-4) ◽  
pp. 753-762 ◽  
Author(s):  
A. F. Rozich
Keyword(s):  
Activated Sludge ◽  
Model Calibration ◽  
Process Model ◽  
Process Analysis ◽  
Case Histories ◽  
Model Case ◽  
Operational Strategies ◽  
Analysis Methodology ◽  
Technical Basis ◽  
Activated Sludge Processes

The purpose of this paper is to present the background and examples of methodology which enable environmental engineers and scientists to analyze activated sludge processes much more effectively than is otherwise possible with conventional approaches. Good process analyses are key for devising optimal design and operational strategies. The key features to the technique presented herein are the field-proven predictability of the model and the methodology for collecting data needed for calibrating the process model. Case histories prove the predictability of the model that is associated with the process analysis approach. The advantage of the approach advocated herein is the use of respirometric techniques to calibrate the model. These methods enable the process analyst to collect the requisite data for model calibration in twenty-four hours or less. This feature enables one to use this process analysis methodology for both design and operational applications. The paper will present the technical basis for the process model and how respirometric methods are utilized to compute biokinetic constants in a manner which is consistent with kinetic theory. Case histories will be discussed that demonstrate the predictability of the modeling approach and demonstrate the utility of this tool for process analysis.

scholarly journals Wetting front dynamics in an isotropic porous medium

2012 ◽  
Vol 694 ◽  
pp. 399-407 ◽  
Author(s):  
Yulii D. Shikhmurzaev ◽  
James E. Sprittles
Keyword(s):  
Porous Medium ◽  
Incompressible Liquid ◽  
Porous Matrix ◽  
Viscous Incompressible Liquid ◽  
Pore Scale ◽  
Wetting Front ◽  
Model Case ◽  
New Approach ◽  
Threshold Phenomena ◽  
Front Dynamics

AbstractA new approach to the modelling of wetting fronts in porous media on the Darcy scale is developed, based on considering the types (modes) of motion the menisci go through on the pore scale. This approach is illustrated using a simple model case of imbibition of a viscous incompressible liquid into an isotropic porous matrix with two modes of motion for the menisci, the wetting mode and the threshold mode. The latter makes it necessary to introduce an essentially new technique of conjugate problems that allows one to link threshold phenomena on the pore scale with the motion on the Darcy scale. The developed approach (a) makes room for incorporating the actual physics of wetting on the pore scale, (b) brings in the physics associated with pore-scale thresholds, which determine when sections of the wetting front will be brought to a halt (pinned), and, importantly, (c) provides a regular framework for constructing models of increasing complexity.

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