The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Stephen Nowicki - One of the best experts on this subject based on the ideXlab platform.
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vocal performance influences female response to male bird song an experimental test
Behavioral Ecology, 2004Co-Authors: Barbara Ballentine, Jeremy Hyman, Stephen NowickiAbstract:Female songbirds are thought to assess males based on aspects of song, such as repertoire size or amount of singing, that could potentially provide information about male quality. A relatively unexplored aspect of song that also might serve as an assessment signal is a male’s ability to perform physically challenging songs. Trilled songs, such as those produced by swamp sparrows (Melospiza georgiana), present males with a performance challenge because trills require rapid and precise coordination of vocal tract movements, resulting in a trade-off between trill rate and frequency bandwidth. This trade-off defines a constraint on song production observed as a Triangular Distribution in acoustic space of trill rate by frequency bandwidth, with an upper boundary that represents a performance limit. Given this background on song production constraints, we are able to identify a priori which songs are performed with a higher degree of proficiency and, thus, which songs should be more attractive to females. We determined the performance limit for a population of swamp sparrows and measured how well individual males performed songs relative to this limit (‘‘vocal performance’’). We then compared female solicitation responses to high-performance versus lowperformance versions of the same song type produced by different males. Females displayed significantly more to highperformance songs than to low-performance songs, supporting the hypothesis that females use vocal performance to assess males. Key words: bird song, female choice, indicator mechanism, Melospiza georgiana, motor constraint, sexual selection, vocal performance. [Behav Ecol 15:163–168 (2004)]
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vocal performance influences female response to male bird song an experimental test
Behavioral Ecology, 2004Co-Authors: Barbara Ballentine, Jeremy Hyman, Stephen NowickiAbstract:Female songbirds are thought to assess males based on aspects of song, such as repertoire size or amount of singing, that could potentially provide information about male quality. A relatively unexplored aspect of song that also might serve as an assessment signal is a male's ability to perform physically challenging songs. Trilled songs, such as those produced by swamp sparrows (Melospiza georgiana), present males with a performance challenge because trills require rapid and precise coordination of vocal tract movements, resulting in a trade-off between trill rate and frequency bandwidth. This trade-off defines a constraint on song production observed as a Triangular Distribution in acoustic space of trill rate by frequency bandwidth, with an upper boundary that represents a performance limit. Given this background on song production constraints, we are able to identify a priori which songs are performed with a higher degree of proficiency and, thus, which songs should be more attractive to females. We determined the performance limit for a population of swamp sparrows and measured how well individual males performed songs relative to this limit ("vocal performance"). We then compared female solicitation responses to high-performance versus low-performance versions of the same song type produced by different males. Females displayed significantly more to high-performance songs than to low-performance songs, supporting the hypothesis that females use vocal performance to assess males. Copyright 2004.
Barbara Ballentine - One of the best experts on this subject based on the ideXlab platform.
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vocal performance influences female response to male bird song an experimental test
Behavioral Ecology, 2004Co-Authors: Barbara Ballentine, Jeremy Hyman, Stephen NowickiAbstract:Female songbirds are thought to assess males based on aspects of song, such as repertoire size or amount of singing, that could potentially provide information about male quality. A relatively unexplored aspect of song that also might serve as an assessment signal is a male’s ability to perform physically challenging songs. Trilled songs, such as those produced by swamp sparrows (Melospiza georgiana), present males with a performance challenge because trills require rapid and precise coordination of vocal tract movements, resulting in a trade-off between trill rate and frequency bandwidth. This trade-off defines a constraint on song production observed as a Triangular Distribution in acoustic space of trill rate by frequency bandwidth, with an upper boundary that represents a performance limit. Given this background on song production constraints, we are able to identify a priori which songs are performed with a higher degree of proficiency and, thus, which songs should be more attractive to females. We determined the performance limit for a population of swamp sparrows and measured how well individual males performed songs relative to this limit (‘‘vocal performance’’). We then compared female solicitation responses to high-performance versus lowperformance versions of the same song type produced by different males. Females displayed significantly more to highperformance songs than to low-performance songs, supporting the hypothesis that females use vocal performance to assess males. Key words: bird song, female choice, indicator mechanism, Melospiza georgiana, motor constraint, sexual selection, vocal performance. [Behav Ecol 15:163–168 (2004)]
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vocal performance influences female response to male bird song an experimental test
Behavioral Ecology, 2004Co-Authors: Barbara Ballentine, Jeremy Hyman, Stephen NowickiAbstract:Female songbirds are thought to assess males based on aspects of song, such as repertoire size or amount of singing, that could potentially provide information about male quality. A relatively unexplored aspect of song that also might serve as an assessment signal is a male's ability to perform physically challenging songs. Trilled songs, such as those produced by swamp sparrows (Melospiza georgiana), present males with a performance challenge because trills require rapid and precise coordination of vocal tract movements, resulting in a trade-off between trill rate and frequency bandwidth. This trade-off defines a constraint on song production observed as a Triangular Distribution in acoustic space of trill rate by frequency bandwidth, with an upper boundary that represents a performance limit. Given this background on song production constraints, we are able to identify a priori which songs are performed with a higher degree of proficiency and, thus, which songs should be more attractive to females. We determined the performance limit for a population of swamp sparrows and measured how well individual males performed songs relative to this limit ("vocal performance"). We then compared female solicitation responses to high-performance versus low-performance versions of the same song type produced by different males. Females displayed significantly more to high-performance songs than to low-performance songs, supporting the hypothesis that females use vocal performance to assess males. Copyright 2004.
Jeremy Hyman - One of the best experts on this subject based on the ideXlab platform.
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vocal performance influences female response to male bird song an experimental test
Behavioral Ecology, 2004Co-Authors: Barbara Ballentine, Jeremy Hyman, Stephen NowickiAbstract:Female songbirds are thought to assess males based on aspects of song, such as repertoire size or amount of singing, that could potentially provide information about male quality. A relatively unexplored aspect of song that also might serve as an assessment signal is a male’s ability to perform physically challenging songs. Trilled songs, such as those produced by swamp sparrows (Melospiza georgiana), present males with a performance challenge because trills require rapid and precise coordination of vocal tract movements, resulting in a trade-off between trill rate and frequency bandwidth. This trade-off defines a constraint on song production observed as a Triangular Distribution in acoustic space of trill rate by frequency bandwidth, with an upper boundary that represents a performance limit. Given this background on song production constraints, we are able to identify a priori which songs are performed with a higher degree of proficiency and, thus, which songs should be more attractive to females. We determined the performance limit for a population of swamp sparrows and measured how well individual males performed songs relative to this limit (‘‘vocal performance’’). We then compared female solicitation responses to high-performance versus lowperformance versions of the same song type produced by different males. Females displayed significantly more to highperformance songs than to low-performance songs, supporting the hypothesis that females use vocal performance to assess males. Key words: bird song, female choice, indicator mechanism, Melospiza georgiana, motor constraint, sexual selection, vocal performance. [Behav Ecol 15:163–168 (2004)]
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vocal performance influences female response to male bird song an experimental test
Behavioral Ecology, 2004Co-Authors: Barbara Ballentine, Jeremy Hyman, Stephen NowickiAbstract:Female songbirds are thought to assess males based on aspects of song, such as repertoire size or amount of singing, that could potentially provide information about male quality. A relatively unexplored aspect of song that also might serve as an assessment signal is a male's ability to perform physically challenging songs. Trilled songs, such as those produced by swamp sparrows (Melospiza georgiana), present males with a performance challenge because trills require rapid and precise coordination of vocal tract movements, resulting in a trade-off between trill rate and frequency bandwidth. This trade-off defines a constraint on song production observed as a Triangular Distribution in acoustic space of trill rate by frequency bandwidth, with an upper boundary that represents a performance limit. Given this background on song production constraints, we are able to identify a priori which songs are performed with a higher degree of proficiency and, thus, which songs should be more attractive to females. We determined the performance limit for a population of swamp sparrows and measured how well individual males performed songs relative to this limit ("vocal performance"). We then compared female solicitation responses to high-performance versus low-performance versions of the same song type produced by different males. Females displayed significantly more to high-performance songs than to low-performance songs, supporting the hypothesis that females use vocal performance to assess males. Copyright 2004.
Kwong Wing Chau - One of the best experts on this subject based on the ideXlab platform.
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monte carlo simulation of construction costs using subjective data
Construction Management and Economics, 1995Co-Authors: Kwong Wing ChauAbstract:This paper critically examines the problems arising from the assumptions of independence and Triangular Distribution in the risk analysis of construction costs. These two assumptions have been widely adopted by researchers and practitioners alike. However, they lead to bias in the analysis. With the aid of a spreadsheet and a risk analysis add-on program, the nature of the resulting bias can be illustrated using both empirical and simulated data. Various possible solutions which seek to reduce the bias are explored. Their practicality under real life constraints is examined. A tentative practical solution is proposed and evaluated against the existing approach. The method and logic of the solution are also discussed. The approach is applied to two sets of data to illustrate its use and to test the reasonableness of the approach.
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The validity of the Triangular Distribution assumption in Monte Carlo simulation of construction costs: empirical evidence from Hong Kong
Construction Management and Economics, 1995Co-Authors: Kwong Wing ChauAbstract:This paper investigates the validity of the Triangular Distribution assumption which is commonly adopted in Monte Carlo simulations of construction costs. The study begins with an examination of the asymmetric nature of the Distribution of construction costs and deduces theoretically that the Triangular Distribution assumption leads to an upward bias in the probability of exceeding the conventional single figure estimate for the subsystem variables and therefore the system variable. This assumption is also inconsistent with the estimators' subjective perception. An experiment has been performed to generate empirical data that test the above theoretical arguments and assesses the magnitude of the bias, if it indeed exists. Subjective estimates of the construction costs of the ten major subsystems of electrical services contracts of government clinics in Hong Kong are examined. These estimates are extracted from seven experienced estimators. The results of the analysis of the data confirm that the underlyin...
Ga Zhang - One of the best experts on this subject based on the ideXlab platform.
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centrifuge model test study on pile reinforcement behavior of cohesive soil slopes under earthquake conditions
Landslides, 2014Co-Authors: Liping P Wang, Ga ZhangAbstract:In this study, dynamic centrifuge model tests were conducted to investigate the dynamic response of cohesive soil slopes with the use of stabilizing piles during an earthquake. The behavior of the pile reinforcement was analyzed based on the obtained deformation over the entire slope through image-based measurement, and the behavior of the slope was compared to that of an unreinforced slope. The piles significantly increased the stability of the slope and reduced its deformation during an earthquake. The bending moment of the piles exhibited a nearly Triangular Distribution due to the earthquake. The acceleration response of the slope increased with increasing elevation, and the displacement accumulated apparently irreversibly over the course of the earthquake. The piles significantly affected the deformation of the slope in a certain area, the boundary of which was defined using a continuous surface. A strain analysis of the slope demonstrated that the piles had a significant effect on the reduction in the deformation of the slope in their vicinities, and this effect expanded upward along the slope and arrested the possible slip surface that would have occurred in an unreinforced slope. Several influencing factors were simulated in the tests, and observation of these factors demonstrated that the dynamic response of the pile-reinforced slope was affected by the pile spacing, pile location, slope gradient, and input earthquake to varying extent.
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centrifuge model tests of geotextile reinforced soil embankments during an earthquake
Geotextiles and Geomembranes, 2011Co-Authors: Liping Wang, Ga Zhang, Jianmin ZhangAbstract:Abstract The behavior of geotextile-reinforced embankments during an earthquake was investigated using centrifuge model tests, considering a variety of factors such as gradient of slope, water content of soil, geotextile spacing, and input shaking wave. The geotextile-reinforcement mechanism was revealed on the basis of the observations with comparison of the unreinforced embankment. The geotextile significantly decreases the deformation of the embankment and restricts sliding failure that occurs in the unreinforced embankment during an earthquake. The displacement exhibits an evidently irreversible accumulation with a fluctuation during the earthquake which is significantly dependent on the magnitude of input shaking. The peak strain of the geotextile exhibits a nearly Triangular Distribution in the vertical direction. The embankment can be divided into two zones, a restricting zone and restricted zone , where the soil and geotextile, respectively, play an active restriction role in the soil-geotextile interaction. The soil restricts the geotextile in the restricting zone , and this restriction is transferred to the restricted zone through the geotextile. The strain magnitude of the geotextile and the horizontal displacement of the geotextile-reinforced embankment decrease with increasing geotextile layers, with decreasing water content of the soil, with decreasing gradient of the slope, and with decreasing amplitude of the earthquake wave.
