The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Pablo R Stevenson - One of the best experts on this subject based on the ideXlab platform.

  • scent marking in two western amazonian populations of woolly monkeys lagothrix lagotricha
    American Journal of Primatology, 2006
    Co-Authors: Anthony Di Fiore, Andres Link, Pablo R Stevenson
    Abstract:

    We describe patterns of scent marking observed in two wild populations of lowland woolly monkeys that were the subjects of long-term studies in the westernmost portion of the Amazon basin. The woolly monkeys engaged primarily in two types of scent marking: chest rubbing and anogenital rubbing. In both study populations, males and females performed both types of scent marking, but males chest-rubbed more commonly than females, while females engaged in more anogenital rubbing. We evaluated two nonexclusive hypotheses for the function of scent marking by woolly monkeys: 1) that scent marking is used in sociosexual contexts, and 2) that scent marking is used to convey information about occupancy of or willingness to defend an area from conspecifics in other social groups. We found no association between the occurrence of scent-marking behavior and location within the home range, but did find that scent marking occurred more commonly than expected on days when copulations, mating solicitations, and intergroup encounters were observed. Additionally, mating activity and chest rubbing were highly correlated across the yearly cycle, even when the potentially Confounding Variable of ripe fruit availability was controlled for. In woolly monkeys, overt male-male competition is rare and female choice is an important part of the mating system. Our results are most consistent with the idea that scent marking plays a role in advertising male quality or competitive ability, and perhaps in coordinating mating activity.

  • research article scent marking in two western amazonian populations of woolly monkeys lagothrix lagotricha
    2006
    Co-Authors: Anthony Di Fiore, Andres Link, Pablo R Stevenson
    Abstract:

    We describe patterns of scent marking observed in two wild populations of lowland woolly monkeys that were the subjects of long-term studies in the westernmost portion of the Amazon basin. The woolly monkeys engaged primarily in two types of scent marking: chest rubbing and anogenital rubbing. In both study populations, males and females performed both types of scent marking, but males chest-rubbed more commonly than females, while females engaged in more anogenital rubbing. We evaluated two nonexclusive hypotheses for the function of scent marking by woolly monkeys: 1) that scent marking is used in sociosexual contexts, and 2) that scent marking is used to convey information about occupancy of or willingness to defend an area from conspecifics in other social groups. We found no association between the occurrence of scent-marking behavior and location within the home range, but did find that scent marking occurred more commonly than expected on days when copulations, mating solicitations, and intergroup encounters were observed. Additionally, mating activity and chest rubbing were highly correlated across the yearly cycle, even when the potentially Confounding Variable of ripe fruit availability was controlled for. In woolly monkeys, overt male‐male competition is rare and female choice is an important part of the mating system. Our results are most consistent with the idea that scent marking plays a role in advertising male quality or competitive ability, and perhaps in coordinating mating activity. Am. J. Primatol. 68:637‐649, 2006. c 2006 Wiley-Liss, Inc.

Anthony Di Fiore - One of the best experts on this subject based on the ideXlab platform.

  • scent marking in two western amazonian populations of woolly monkeys lagothrix lagotricha
    American Journal of Primatology, 2006
    Co-Authors: Anthony Di Fiore, Andres Link, Pablo R Stevenson
    Abstract:

    We describe patterns of scent marking observed in two wild populations of lowland woolly monkeys that were the subjects of long-term studies in the westernmost portion of the Amazon basin. The woolly monkeys engaged primarily in two types of scent marking: chest rubbing and anogenital rubbing. In both study populations, males and females performed both types of scent marking, but males chest-rubbed more commonly than females, while females engaged in more anogenital rubbing. We evaluated two nonexclusive hypotheses for the function of scent marking by woolly monkeys: 1) that scent marking is used in sociosexual contexts, and 2) that scent marking is used to convey information about occupancy of or willingness to defend an area from conspecifics in other social groups. We found no association between the occurrence of scent-marking behavior and location within the home range, but did find that scent marking occurred more commonly than expected on days when copulations, mating solicitations, and intergroup encounters were observed. Additionally, mating activity and chest rubbing were highly correlated across the yearly cycle, even when the potentially Confounding Variable of ripe fruit availability was controlled for. In woolly monkeys, overt male-male competition is rare and female choice is an important part of the mating system. Our results are most consistent with the idea that scent marking plays a role in advertising male quality or competitive ability, and perhaps in coordinating mating activity.

  • research article scent marking in two western amazonian populations of woolly monkeys lagothrix lagotricha
    2006
    Co-Authors: Anthony Di Fiore, Andres Link, Pablo R Stevenson
    Abstract:

    We describe patterns of scent marking observed in two wild populations of lowland woolly monkeys that were the subjects of long-term studies in the westernmost portion of the Amazon basin. The woolly monkeys engaged primarily in two types of scent marking: chest rubbing and anogenital rubbing. In both study populations, males and females performed both types of scent marking, but males chest-rubbed more commonly than females, while females engaged in more anogenital rubbing. We evaluated two nonexclusive hypotheses for the function of scent marking by woolly monkeys: 1) that scent marking is used in sociosexual contexts, and 2) that scent marking is used to convey information about occupancy of or willingness to defend an area from conspecifics in other social groups. We found no association between the occurrence of scent-marking behavior and location within the home range, but did find that scent marking occurred more commonly than expected on days when copulations, mating solicitations, and intergroup encounters were observed. Additionally, mating activity and chest rubbing were highly correlated across the yearly cycle, even when the potentially Confounding Variable of ripe fruit availability was controlled for. In woolly monkeys, overt male‐male competition is rare and female choice is an important part of the mating system. Our results are most consistent with the idea that scent marking plays a role in advertising male quality or competitive ability, and perhaps in coordinating mating activity. Am. J. Primatol. 68:637‐649, 2006. c 2006 Wiley-Liss, Inc.

Andres Link - One of the best experts on this subject based on the ideXlab platform.

  • scent marking in two western amazonian populations of woolly monkeys lagothrix lagotricha
    American Journal of Primatology, 2006
    Co-Authors: Anthony Di Fiore, Andres Link, Pablo R Stevenson
    Abstract:

    We describe patterns of scent marking observed in two wild populations of lowland woolly monkeys that were the subjects of long-term studies in the westernmost portion of the Amazon basin. The woolly monkeys engaged primarily in two types of scent marking: chest rubbing and anogenital rubbing. In both study populations, males and females performed both types of scent marking, but males chest-rubbed more commonly than females, while females engaged in more anogenital rubbing. We evaluated two nonexclusive hypotheses for the function of scent marking by woolly monkeys: 1) that scent marking is used in sociosexual contexts, and 2) that scent marking is used to convey information about occupancy of or willingness to defend an area from conspecifics in other social groups. We found no association between the occurrence of scent-marking behavior and location within the home range, but did find that scent marking occurred more commonly than expected on days when copulations, mating solicitations, and intergroup encounters were observed. Additionally, mating activity and chest rubbing were highly correlated across the yearly cycle, even when the potentially Confounding Variable of ripe fruit availability was controlled for. In woolly monkeys, overt male-male competition is rare and female choice is an important part of the mating system. Our results are most consistent with the idea that scent marking plays a role in advertising male quality or competitive ability, and perhaps in coordinating mating activity.

  • research article scent marking in two western amazonian populations of woolly monkeys lagothrix lagotricha
    2006
    Co-Authors: Anthony Di Fiore, Andres Link, Pablo R Stevenson
    Abstract:

    We describe patterns of scent marking observed in two wild populations of lowland woolly monkeys that were the subjects of long-term studies in the westernmost portion of the Amazon basin. The woolly monkeys engaged primarily in two types of scent marking: chest rubbing and anogenital rubbing. In both study populations, males and females performed both types of scent marking, but males chest-rubbed more commonly than females, while females engaged in more anogenital rubbing. We evaluated two nonexclusive hypotheses for the function of scent marking by woolly monkeys: 1) that scent marking is used in sociosexual contexts, and 2) that scent marking is used to convey information about occupancy of or willingness to defend an area from conspecifics in other social groups. We found no association between the occurrence of scent-marking behavior and location within the home range, but did find that scent marking occurred more commonly than expected on days when copulations, mating solicitations, and intergroup encounters were observed. Additionally, mating activity and chest rubbing were highly correlated across the yearly cycle, even when the potentially Confounding Variable of ripe fruit availability was controlled for. In woolly monkeys, overt male‐male competition is rare and female choice is an important part of the mating system. Our results are most consistent with the idea that scent marking plays a role in advertising male quality or competitive ability, and perhaps in coordinating mating activity. Am. J. Primatol. 68:637‐649, 2006. c 2006 Wiley-Liss, Inc.

Philippe Grandjean - One of the best experts on this subject based on the ideXlab platform.

  • negative Confounding in the evaluation of toxicity the case of methylmercury in fish and seafood
    Critical Reviews in Toxicology, 2008
    Co-Authors: Anna L Choi, Sylvaine Cordier, Pal Weihe, Philippe Grandjean
    Abstract:

    In observational studies, the presence of Confounding can distort the true association between an exposure and a toxic effect outcome if the Confounding Variable is not controlled either in the study design or the analysis phase. While Confounding is often assumed to occur in the same direction as the toxicant exposure, the relationship between the benefits and risks associated with fish and seafood consumption is a classic example of negative Confounding: the exposure to methylmercury occurs from fish and seafood which are also associated with beneficial nutrients, thereby counteracting the signs of mercury toxicity. Mercury and nutrients may affect the same epidemiological outcomes, but most studies addressing one of them have ignored the potential negative Confounding by the other. This article reviews the existing evidence of effects of both nutrient and contaminant intakes as predictors of neurodevelopmental and cardiovascular outcomes. Substantial underestimation of the effects of mercury toxicity and fish benefits occurs from the lack of confounder adjustment and imprecision of the exposure parameters. Given this inherent bias in observational studies, regulatory agencies should reconsider current dietary advisories to provide better guidance to consumers in making prudent choices to maintain a nutritious diet with seafood that is low in mercury concentrations. Attention should also be paid to the occurrence of negative Confounding in other connections.

  • Negative Confounding in the evaluation of toxicity: the case of methylmercury in fish and seafood.
    Critical Reviews in Toxicology, 2008
    Co-Authors: Anna L Choi, Sylvaine Cordier, Pal Weihe, Philippe Grandjean
    Abstract:

    In observational studies, the presence of Confounding [corrected] can distort the true association between an exposure and a toxic-effect outcome, if the Confounding Variable is not controlled for in the study design or analysis phase. While Confounding is often assumed to occur in the same direction as the toxicant exposure, the relationship between the benefits and risks associated with fish and seafood consumption is a classic example of negative Confounding: the exposure to methylmercury occurs with fish and seafood, which are also associated with beneficial nutrients, and the signs of mercury toxicity [corrected] Mercury and nutrients may affect the same epidemiological outcomes, but most studies addressing one of them have ignored the potential for negative Confounding by the other. This article reviews the existing evidence of effects of both nutrient and contaminant intakes as predictors of neurodevelopmental and cardiovascular outcomes. Substantial underestimation of the effects of mercury toxicity and of fish benefits occurs from the lack of confounder adjustment and imprecision of the exposure parameters. Given this inherent bias in observational studies, regulatory agencies should reconsider current dietary advice in order to provide better guidance to consumers in making prudent choices to maintain a nutritious diet with seafood that is low in mercury concentrations. Attention should also be paid to the occurrence of negative Confounding in other connections.

Sreeni Pathirana - One of the best experts on this subject based on the ideXlab platform.

  • SUCROSE DETECTION AND THE STABILITY OF THE 2-AFC PROCEDURE IN THE PRESENCE OF A Confounding Variable
    Journal of Sensory Studies, 2008
    Co-Authors: Daniel Shepherd, Siew Young Quek, Sreeni Pathirana
    Abstract:

    This study attempted to measure absolute thresholds for sucrose in aqueous solution for 51 experienced judges. Two experiments utilizing the two-alternative forced-choice (2-AFC) procedure generated 6-point psychometric functions plotting percentage correct as a function of sucrose concentration. In both experiments, the judges were divided into two groups and tested in either purpose-built sensory booths or on open tables situated in a laboratory. In the first experiment, the influence of a Confounding Variable was apparent, with nonmonotonic psychometric functions being obtained. In experiment II, the Confounding Variable was eliminated, permitting the estimation of absolute thresholds. In both experiments, there was no main effect of gender or session, though there was an effect of testing locality (P 

  • sucrose detection and the stability of the 2 afc procedure in the presence of a Confounding Variable
    Journal of Sensory Studies, 2008
    Co-Authors: Daniel Shepherd, Siew Young Quek, Sreeni Pathirana
    Abstract:

    This study attempted to measure absolute thresholds for sucrose in aqueous solution for 51 experienced judges. Two experiments utilizing the two-alternative forced-choice (2-AFC) procedure generated 6-point psychometric functions plotting percentage correct as a function of sucrose concentration. In both experiments, the judges were divided into two groups and tested in either purpose-built sensory booths or on open tables situated in a laboratory. In the first experiment, the influence of a Confounding Variable was apparent, with nonmonotonic psychometric functions being obtained. In experiment II, the Confounding Variable was eliminated, permitting the estimation of absolute thresholds. In both experiments, there was no main effect of gender or session, though there was an effect of testing locality (P < 0.05). Data are reported to emphasize the importance of controlling extraneous Variables and to demonstrate the robustness of the 2-AFC procedure. PRACTICAL APPLICATIONS This research contributes to an otherwise impoverished database on the detection of sucrose in a solution. The uses of the research include estimates of sucrose detection thresholds for comparative purposes; confirmation of the stability of the two-alternative forced-choice procedure; the utility of using formal testing areas as opposed to ad hoc testing stations; and the dangers of utilizing substandard experimental equipment while conducting research of this nature.