Minimal-Time k-Line Broadcasting

Orientation mechanisms allow animals to spend minimal time in hostile areas while reaching needed resources. Identification of the specific mechanism used by an animal can be difficult, but examining an animal's path in familiar and unfamiliar areas can provide clues to the type of mechanism in use. Semiaquatic turtles are known to use a homing mechanism in familiar territory to locate their home lake while on land, but little is known about their ability to locate habitat in unfamiliar territory. We tested the tortuosity and orientation of 60 eastern painted turtles ( Chrysemys picta picta (Schneider, 1783)). We released turtles at 20 release points located at five distances and in two directions from two unfamiliar lakes. Turtle trails were quite straight (fractal dimension between 1.1 and 1.025) but were not oriented towards water from any distance (V-test; u < 0.72; P > 0.1). Turtles maintained their initially chosen direction but either could not detect water or were not motivated to reach it. Furthermore, paths were straighter at larger spatial scales than at smaller spatial scales, which could not have occurred if the turtles had been using a correlated random walk. Turtles must therefore be using a reference stimulus for navigation even in unfamiliar areas.

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Minimal time control problem of a linear heat equation with memory

Systems & Control Letters ◽

10.1016/j.sysconle.2021.105052 ◽

2021 ◽

Vol 157 ◽

pp. 105052

Author(s):

Lijuan Wang ◽

Xiuxiang Zhou

Keyword(s):

Heat Equation ◽

Control Problem ◽

Linear Heat Equation ◽

Linear Heat ◽

Minimal Time ◽

Time Control ◽

Heat Equation With Memory ◽

With Memory

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Anthropometric comparison of muscular and obese men

Journal of Applied Physiology ◽

10.1152/jappl.1961.16.6.955 ◽

1961 ◽

Vol 16 (6) ◽

pp. 955-959 ◽

Cited By ~ 77

Author(s):

W. Leonard Taylor ◽

Albert R. Behnke

Keyword(s):

Body Weight ◽

Anthropometric Data ◽

Reference Base ◽

Minimal Time ◽

Tape Measure ◽

Large Numbers ◽

Special Apparatus ◽

Physiologic Parameters ◽

D Values

Body weight is frequently too gross as a reference base for physiologic parameters. Adequate techniques are available to measure such components as water and fat, but these procedures are time consuming and require special apparatus. The high correlation, however, between anthropometric circumferences, stature, and body weight makes possible a partition of weight into components, W( A) and W( B). In obese men it can be shown that the “trunk” W( A) component greatly exceeds the weight of W( B) referable chiefly to the extremities. In athletes, W( B) exceeds W( A). The average of W( A) and W( B) closely approximates body weight. From the anthropometric perimeters it is possible to calculate d values which can be used to construct a somatogram to provide quantitative representation of bodily configuration. The technique for procurement of the anthropometric data can be carried out on large numbers of individuals in minimal time and requires only a tape measure. Submitted on April 28, 1961

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