Management of fat reserves in tufted titmice ( Parus bicolor  ): evidence against a trade-off with food hoards

1998 ◽  
Vol 42 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Vladimir V. Pravosudov ◽  
Thomas C. Grubb Jr.
Keyword(s):  
Trade Off ◽  
Fat Reserves ◽  
Parus Bicolor

scholarly journals Mass-dependent predation risk and lethal dolphin–porpoise interactions

2007 ◽  
Vol 274 (1625) ◽  
pp. 2587-2593 ◽  
Author(s):  
R MacLeod ◽  
C.D MacLeod ◽  
J.A Learmonth ◽  
P.D Jepson ◽  
R.J Reid ◽  
...  
Keyword(s):  
Predation Risk ◽  
Bottlenose Dolphins ◽  
Flight Performance ◽  
Energy Reserves ◽  
Trade Off ◽  
Fat Reserves ◽  
Ecological Principle ◽  
Mass Dependent ◽  
Starvation Risk ◽  
Individual Mass

In small birds, mass-dependent predation risk (MDPR) is known to make the trade-off between avoiding starvation and avoiding predation dependent on individual mass. This occurs because carrying increased fat reserves not only reduces starvation risk but also results in a higher predation risk due to reduced escape flight performance and/or the increased foraging exposure needed to maintain a higher body mass. In principle, the theory of MDPR could also apply to any animal capable of storing energy reserves to reduce starvation and whose escape performance decreases with increasing mass. We used a unique situation along certain parts of coastal Britain, where harbour porpoises ( Phocoena phocoena ) are pursued and killed but crucially not eaten by bottlenose dolphins ( Tursiops truncatus ), to investigate whether a MDPR effect can occur in non-avian species. We show that where high levels of dolphin ‘predation’ occur, porpoises carry significantly less energy reserves than would otherwise be expected and this equates to reducing by approximately 37% the length of time that a porpoise could survive without feeding. These results provide the first evidence that a mass-dependent starvation–predation risk trade-off may be a general ecological principle that can apply to widely different animal types rather than, as is currently thought, only to birds.

A Flow-Preserving Algorithm for the Time-Cost Trade-Off Problem

1982 ◽  
Vol 14 (2) ◽  
pp. 109-113 ◽  
Author(s):  
Suleyman Tufekci
Keyword(s):  
Time Cost ◽  
Trade Off

Dual Goals for Speed and Accuracy on the Same Performance Task

2012 ◽  
Vol 11 (3) ◽  
pp. 118-126 ◽  
Author(s):  
Olive Emil Wetter ◽  
Jürgen Wegge ◽  
Klaus Jonas ◽  
Klaus-Helmut Schmidt
Keyword(s):  
Memory Scanning ◽  
Performance Task ◽  
Performance Tasks ◽  
Trade Off ◽  
Test Experiment ◽  
Trade Offs ◽  
New Finding ◽  
Sternberg Paradigm ◽  
Speed Accuracy ◽  
Speed And Accuracy

In most work contexts, several performance goals coexist, and conflicts between them and trade-offs can occur. Our paper is the first to contrast a dual goal for speed and accuracy with a single goal for speed on the same task. The Sternberg paradigm (Experiment 1, n = 57) and the d2 test (Experiment 2, n = 19) were used as performance tasks. Speed measures and errors revealed in both experiments that dual as well as single goals increase performance by enhancing memory scanning. However, the single speed goal triggered a speed-accuracy trade-off, favoring speed over accuracy, whereas this was not the case with the dual goal. In difficult trials, dual goals slowed down scanning processes again so that errors could be prevented. This new finding is particularly relevant for security domains, where both aspects have to be managed simultaneously.

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