... Eun-ah Cho, A. John Bailer, and James T ... The frequent presence and associated problems... more ... Eun-ah Cho, A. John Bailer, and James T ... The frequent presence and associated problems of MTBE in surface water and groundwater resulted in a request from the US EPA to Congress to consider legislation that would significantly reduce or eliminate the use of MTBE (11). ...
The toxic equivalency factor (TEF) method has been used to characterize the toxicity of human mix... more The toxic equivalency factor (TEF) method has been used to characterize the toxicity of human mixtures of dioxin-like compounds and is being considered for use with other classes of potentially toxic agents. TEFs are estimated by examining the relative potencies of the various congeners for a series of biological and toxicological effects. In this paper, we consider changes in activity for two enzymes, cytochrome P450 1A1 (CYP1A1)-associated 7-ethoxyresorufin-O-deethylase (EROD) and CYP1A2-associated acetanilide-4-hydroxylase (A4H) activity, resulting from exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3',4,4',5-pentachlorobiphenyl (PCB), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) or a mixture of these agents. The ratio of median effective dose (ED50) is one way to estimate the relative potencies, especially for gene expression and protein endpoints. ED50's were estimated with a nonlinear regression model in which dose-related changes in mean responses are described by a Hill function. ED50's along with other model parameters were estimated by fitting this model to a given data set. Significant differences in estimated model parameters were tested by likelihood ratio methods. The estimated parameters indicated that congener-specific dose-response shapes were significantly different, that additivity failed for these congeners, and that the ratios of ED50's did not predict the response seen for the mixture. These results indicate that for some biological responses, the use of a single relative potency factor (RPF) is not appropriate for the comparison of the dose response behavior of different dioxin-like congeners.
Http Dx Doi Org 10 1080 20028091057501, Jun 3, 2010
... A. John Bailer,* Michael R. Hughes, Kyoungah See, Robert Noble, and Robert Schaefer Center fo... more ... A. John Bailer,* Michael R. Hughes, Kyoungah See, Robert Noble, and Robert Schaefer Center for Environmental Toxicology and Statistics ... Dwayne Moore, Eric Smith, Trefor Reynoldson, Peter Chapman, and Allen Burton for their comments on previous versions of this manu ...
... Vineis P, Schulte PA, Carreón T, Bailer AJ, Medvedovic M. Department of Biomedical Science an... more ... Vineis P, Schulte PA, Carreón T, Bailer AJ, Medvedovic M. Department of Biomedical Science and Human Oncology, University of Turin, Torino, Italy. paolo.vineis@unito.it. PMID: 15055309 [PubMed - indexed for MEDLINE]. Publication Types: ...
ABSTRACT Aquatic toxicity tests are statistically evaluated by either hypothesis testing procedur... more ABSTRACT Aquatic toxicity tests are statistically evaluated by either hypothesis testing procedures to derive a no-observed-effect concentration or by inverting regression models to calculate the concentration associated with a specific reduction from the control response. These latter methods can be described as potency estimation methods. Standard U.S. Environmental Protection Agency (U.S. EPA) potency estimation methods are based on two different techniques. For continuous or count response data, a nominally nonparametric method that assumes monotonic decreasing responses and piecewise linear patterns between successive concentration groups is used. For quantal responses, a probit regression model with a linear dose term is fit. These techniques were compared with a recently developed parametric regression-based estimator, the relative inhibition estimator, RIp. This method is based on fitting generalized linear models, followed by estimation of the concentration associated with a particular decrement relative to control responses. These estimators, with levels of inhibition (p) of 25 and 50%, were applied to a series of chronic toxicity tests in a U.S. EPA region 9 database of reference toxicity tests. Biological responses evaluated in these toxicity tests included the number of young produced in three broods by the water flea (Ceriodaphnia dubia) and germination success and tube length data from the giant kelp (Macrocystis pyrifera). The greatest discrepancy between the RIp and standard U.S. EPA estimators was observed for C. dubia. The concentration–response pattern for this biological endpoint exhibited nonmonotonicity more frequently than for any of the other endpoint. Future work should consider optimal experimental designs to estimate these quantities, methods for constructing confidence intervals, and simulation studies to explore the behavior of these estimators under known conditions.
... by the NORA Traumatic Injury Team. DHHS (NIOSH) No. 98-134, Cincinnati, OH, USA Rosenstock L,... more ... by the NORA Traumatic Injury Team. DHHS (NIOSH) No. 98-134, Cincinnati, OH, USA Rosenstock L, Olenec C, and Wagner GR. 1998. The national occupational research agenda: a model of broad stakeholder input into priority setting. Am J Public Health 88:353-6 Stout NA ...
ABSTRACT Background/Question/Methods: If conservation efforts are to succeed in the long-term, th... more ABSTRACT Background/Question/Methods: If conservation efforts are to succeed in the long-term, the public majority must be scientifically and environmentally literate. Yet, environmental literacy necessitates awareness of and empathy towards nature, and in a time when the majority of the human population resides in urban and suburban environments, many people in the United States have little direct experience with natureand the experience they do have is often through everyday encounters with nearby nature (e.g. small-scale nature that inhabits spaces near work places, schools, homes). To compound the problem, in the past couple decades, the increased dependence on visual technological tools as a means of learning, entertainment and communication (e.g. computers, internet, cellular phones, iPods), is related to the younger generationsthe future stewards of the planetbeing even more distanced from the natural world. However, recent and rapid developments in photographic technology have also created an opportunity by which technology can be used to reconnectand perhaps connect for the first timepeople, and particularly children, with their environment. And the medium of nature photography is becoming more commonly used both towards this end and for increasingly science content knowledge and knowledge about nature of science. Results/Conclusions: We here review and report on several projects across the United States that have used photography, actively and passively, to increase interest in, knowledge about, and active stewardship for nature. Projects reviewd include 1) nature photography workshops for local school children through Minnesota's Digital Bridge to Nature project, 2) citizen science photo documentation in Discover Life in America's All Taxa Biodiversity Inventory project in the Great Smoky Mountains (http://www.dlia.org/atbi/) 3) Antarctic research scientists communicating their work to Ohio classrooms local to the researchers' home institutions (http://frozenfly.edublogs.org/) via blogging with still imagey and interactive online Gigapan images, a project made possible through participation in Carnegie Mellon University's Fine Outreach for Science program (www.gigapan.org), and 4) local-based nature photography talks and exhibits stressing school-yard inquiry teaching methods and place-based education to K-12 educators enrolled in professional development courses with Project Dragonfly (www.projectdragonfly.org) at the Cincinnati Zoo and Botanical Garden, among others. Positive outcomes and challenges will be discussed, as will ideas for other potential ways educators and researchers have and can collaborate with nature photographers locally in order to engage parents, teachers and children in formal and informal environmental and science learning environments.
... Eun-ah Cho, A. John Bailer, and James T ... The frequent presence and associated problems... more ... Eun-ah Cho, A. John Bailer, and James T ... The frequent presence and associated problems of MTBE in surface water and groundwater resulted in a request from the US EPA to Congress to consider legislation that would significantly reduce or eliminate the use of MTBE (11). ...
The toxic equivalency factor (TEF) method has been used to characterize the toxicity of human mix... more The toxic equivalency factor (TEF) method has been used to characterize the toxicity of human mixtures of dioxin-like compounds and is being considered for use with other classes of potentially toxic agents. TEFs are estimated by examining the relative potencies of the various congeners for a series of biological and toxicological effects. In this paper, we consider changes in activity for two enzymes, cytochrome P450 1A1 (CYP1A1)-associated 7-ethoxyresorufin-O-deethylase (EROD) and CYP1A2-associated acetanilide-4-hydroxylase (A4H) activity, resulting from exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3',4,4',5-pentachlorobiphenyl (PCB), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) or a mixture of these agents. The ratio of median effective dose (ED50) is one way to estimate the relative potencies, especially for gene expression and protein endpoints. ED50's were estimated with a nonlinear regression model in which dose-related changes in mean responses are described by a Hill function. ED50's along with other model parameters were estimated by fitting this model to a given data set. Significant differences in estimated model parameters were tested by likelihood ratio methods. The estimated parameters indicated that congener-specific dose-response shapes were significantly different, that additivity failed for these congeners, and that the ratios of ED50's did not predict the response seen for the mixture. These results indicate that for some biological responses, the use of a single relative potency factor (RPF) is not appropriate for the comparison of the dose response behavior of different dioxin-like congeners.
Http Dx Doi Org 10 1080 20028091057501, Jun 3, 2010
... A. John Bailer,* Michael R. Hughes, Kyoungah See, Robert Noble, and Robert Schaefer Center fo... more ... A. John Bailer,* Michael R. Hughes, Kyoungah See, Robert Noble, and Robert Schaefer Center for Environmental Toxicology and Statistics ... Dwayne Moore, Eric Smith, Trefor Reynoldson, Peter Chapman, and Allen Burton for their comments on previous versions of this manu ...
... Vineis P, Schulte PA, Carreón T, Bailer AJ, Medvedovic M. Department of Biomedical Science an... more ... Vineis P, Schulte PA, Carreón T, Bailer AJ, Medvedovic M. Department of Biomedical Science and Human Oncology, University of Turin, Torino, Italy. paolo.vineis@unito.it. PMID: 15055309 [PubMed - indexed for MEDLINE]. Publication Types: ...
ABSTRACT Aquatic toxicity tests are statistically evaluated by either hypothesis testing procedur... more ABSTRACT Aquatic toxicity tests are statistically evaluated by either hypothesis testing procedures to derive a no-observed-effect concentration or by inverting regression models to calculate the concentration associated with a specific reduction from the control response. These latter methods can be described as potency estimation methods. Standard U.S. Environmental Protection Agency (U.S. EPA) potency estimation methods are based on two different techniques. For continuous or count response data, a nominally nonparametric method that assumes monotonic decreasing responses and piecewise linear patterns between successive concentration groups is used. For quantal responses, a probit regression model with a linear dose term is fit. These techniques were compared with a recently developed parametric regression-based estimator, the relative inhibition estimator, RIp. This method is based on fitting generalized linear models, followed by estimation of the concentration associated with a particular decrement relative to control responses. These estimators, with levels of inhibition (p) of 25 and 50%, were applied to a series of chronic toxicity tests in a U.S. EPA region 9 database of reference toxicity tests. Biological responses evaluated in these toxicity tests included the number of young produced in three broods by the water flea (Ceriodaphnia dubia) and germination success and tube length data from the giant kelp (Macrocystis pyrifera). The greatest discrepancy between the RIp and standard U.S. EPA estimators was observed for C. dubia. The concentration–response pattern for this biological endpoint exhibited nonmonotonicity more frequently than for any of the other endpoint. Future work should consider optimal experimental designs to estimate these quantities, methods for constructing confidence intervals, and simulation studies to explore the behavior of these estimators under known conditions.
... by the NORA Traumatic Injury Team. DHHS (NIOSH) No. 98-134, Cincinnati, OH, USA Rosenstock L,... more ... by the NORA Traumatic Injury Team. DHHS (NIOSH) No. 98-134, Cincinnati, OH, USA Rosenstock L, Olenec C, and Wagner GR. 1998. The national occupational research agenda: a model of broad stakeholder input into priority setting. Am J Public Health 88:353-6 Stout NA ...
ABSTRACT Background/Question/Methods: If conservation efforts are to succeed in the long-term, th... more ABSTRACT Background/Question/Methods: If conservation efforts are to succeed in the long-term, the public majority must be scientifically and environmentally literate. Yet, environmental literacy necessitates awareness of and empathy towards nature, and in a time when the majority of the human population resides in urban and suburban environments, many people in the United States have little direct experience with natureand the experience they do have is often through everyday encounters with nearby nature (e.g. small-scale nature that inhabits spaces near work places, schools, homes). To compound the problem, in the past couple decades, the increased dependence on visual technological tools as a means of learning, entertainment and communication (e.g. computers, internet, cellular phones, iPods), is related to the younger generationsthe future stewards of the planetbeing even more distanced from the natural world. However, recent and rapid developments in photographic technology have also created an opportunity by which technology can be used to reconnectand perhaps connect for the first timepeople, and particularly children, with their environment. And the medium of nature photography is becoming more commonly used both towards this end and for increasingly science content knowledge and knowledge about nature of science. Results/Conclusions: We here review and report on several projects across the United States that have used photography, actively and passively, to increase interest in, knowledge about, and active stewardship for nature. Projects reviewd include 1) nature photography workshops for local school children through Minnesota's Digital Bridge to Nature project, 2) citizen science photo documentation in Discover Life in America's All Taxa Biodiversity Inventory project in the Great Smoky Mountains (http://www.dlia.org/atbi/) 3) Antarctic research scientists communicating their work to Ohio classrooms local to the researchers' home institutions (http://frozenfly.edublogs.org/) via blogging with still imagey and interactive online Gigapan images, a project made possible through participation in Carnegie Mellon University's Fine Outreach for Science program (www.gigapan.org), and 4) local-based nature photography talks and exhibits stressing school-yard inquiry teaching methods and place-based education to K-12 educators enrolled in professional development courses with Project Dragonfly (www.projectdragonfly.org) at the Cincinnati Zoo and Botanical Garden, among others. Positive outcomes and challenges will be discussed, as will ideas for other potential ways educators and researchers have and can collaborate with nature photographers locally in order to engage parents, teachers and children in formal and informal environmental and science learning environments.
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