Brian Gray, PhD
Brian Gray
Education and Certifications
Ph.D., Biostatistics, University of South Carolina, 2001
M.S., Biology, University of Kentucky, 1993
Diploma in Natural Resources, Lincoln University, 1982
B.Sc., Botany, University of Auckland, 1981
Science and Products
Filter Total Items: 48
Polychlorinated biphenyls, dioxins, furans, and organochlorine pesticides in belted kingfisher eggs from the upper Hudson River basin, New York, USA
Nesting belted kingfishers (hereafter kingfishers, Ceryle alcyon) were studied on the Hudson River near Fort Edward south to New Baltimore (NY, USA) and three nearby river drainages in 2004. Concentrations of 28 organochlorine pesticides, 160 polychlorinated biphenyl (PCB) congeners, and 17 dioxin and furan (PCDD‐F) congeners were quantified in kingfisher eggs. The pattern of organochlorine pestic
Authors
Thomas W. Custer, Christine M. Custer, Brian R. Gray
Associations between land use and Perkinsus marinus infection of eastern oysters in a high salinity, partially urbanized estuary
Infection levels of eastern oysters by the unicellular pathogen Perkinsus marinus have been associated with anthropogenic influences in laboratory studies. However, these relationships have been difficult to investigate in the field because anthropogenic inputs are often associated with natural influences such as freshwater inflow, which can also affect infection levels. We addressed P. marinus-la
Authors
Brian R. Gray, David Bushek, J. Wanzer Drane, Dwayne Porter
An empirical study of statistical properties of variance partition coefficients for multi-level logistic regression models
Partitioning the variance of a response by design levels is challenging for binomial and other discrete outcomes. Goldstein (2003) proposed four definitions for variance partitioning coefficients (VPC) under a two-level logistic regression model. In this study, we explicitly derived formulae for multi-level logistic regression model and subsequently studied the distributional properties of the cal
Authors
Ji Li, B. R. Gray, D.M. Bates
Effects of methylmercury exposure on the immune function of juvenile common loons (Gavia immer)
We conducted a dose-response laboratory study to quantify the level of exposure to dietary Hg, delivered as methylmercury chloride (CH3HgCl), that is associated with suppressed immune function in captive-reared common loon (Gavia immer) chicks. We used the phytohemagglutinin (PHA) skin test to assess T-lymphocyte function and the sheep red blood cell (SRBC) hemagglutination test to measure antibod
Authors
K.P. Kenow, K.A. Grasman, R. K. Hines, M.W. Meyer, A. Gendron-Fitzpatrick, M. G. Spalding, B. R. Gray
Power to detect trend in short-term time series of bird abundance
Avian point counts for population monitoring are often collected over a short timespan (e.g., 3-5 years). We examined whether power was adequate (power ???0.80) in short-duration studies to warrant the calculation of trend estimates. We modeled power to detect trends in abundance indices of eight bird species occurring across three floodplain habitats (wet prairie, early successional forest, and m
Authors
W.E. Thogmartin, B. R. Gray, M. Gallagher, N. Young, J.J. Rohweder, M. G. Knutson
Estimating trend precision and power to detect trends across grouped count data
Ecologists commonly use grouped or clustered count data to estimate temporal trends in counts, abundance indices, or abundance. For example, the U.S. Breeding Bird Survey data represent multiple counts of birds from within each of multiple, spatially defined routes. Despite a reliance on grouped counts, analytical methods for prospectively estimating precision of trend estimates or statistical pow
Authors
B. R. Gray, M.M. Burlew
Breeding bird territory placement in riparian wet meadows in relation to invasive reed canary grass, Phalaris arundinacea
Invasive plants are a growing concern worldwide for conservation of native habitats. In endangered wet meadow habitat in the Upper Midwestern United States, reed canary grass (Phalaris arundinacea) is a recognized problem and its prevalence is more widespread than the better-known invasive wetland plant purple loosestrife (Lythrum salicaria). Although resource managers are concerned about the effe
Authors
E.M. Kirsch, B. R. Gray, T.J. Fox, W.E. Thogmartin
Chlorophyll a and inorganic suspended solids in backwaters of the upper Mississippi River system: Backwater lake effects and their associations with selected environmental predictors
The Long Term Resource Monitoring Program (LTRMP) uses a stratified random sampling design to obtain water quality statistics within selected study reaches of the Upper Mississippi River System (UMRS). LTRMP sampling strata are based on aquatic area types generally found in large rivers (e.g., main channel, side channel, backwater, and impounded areas). For hydrologically well-mixed strata (i.e.,
Authors
James T. Rogala, Brian R. Gray
Selecting a distributional assumption for modelling relative densities of benthic macroinvertebrates
The selection of a distributional assumption suitable for modelling macroinvertebrate density data is typically challenging. Macroinvertebrate data often exhibit substantially larger variances than expected under a standard count assumption, that of the Poisson distribution. Such overdispersion may derive from multiple sources, including heterogeneity of habitat (historically and spatially), diffe
Authors
B. R. Gray
Modelling habitat associations with fingernail clam (Family: Sphaeriidae) counts at multiple spatial scales using hierarchical count models
1. Macroinvertebrate count data often exhibit nested or hierarchical structure. Examples include multiple measurements along each of a set of streams, and multiple synoptic measurements from each of a set of ponds. With data exhibiting hierarchical structure, outcomes at both sampling (e.g. within stream) and aggregated (e.g. stream) scales are often of interest. Unfortunately, methods for modelli
Authors
Brian R. Gray, Roger J. Haro, James T. Rogala, Jennifer S. Sauer
Agricultural ponds support amphibian populations
In some agricultural regions, natural wetlands are scarce, and constructed agricultural ponds may represent important alternative breeding habitats for amphibians. Properly managed, these agricultural ponds may effectively increase the total amount of breeding habitat and help to sustain populations. We studied small, constructed agricultural ponds in southeastern Minnesota to assess their value a
Authors
M. G. Knutson, W. B. Richardson, D.M. Reineke, B. R. Gray, J.R. Parmelee, S.E. Weick
Flow cytometry used to assess genetic damage in frogs from farm ponds
Flow cytometry (FC) is a laboratory method used to detect genetic damage induced by environmental contaminants and other stressors in animals, including amphibians. We tested FC methods on three species of ranid frogs collected from farm ponds and natural wetlands in southeastern Minnesota. We compared FC metrics for Rana clamitans between ponds with direct exposure to agricultural contaminants an
Authors
B.L. Bly, M. G. Knutson, M.B. Sandheinrich, B. R. Gray, D.A. Jobe
Science and Products
- Data
- Publications
Filter Total Items: 48
Polychlorinated biphenyls, dioxins, furans, and organochlorine pesticides in belted kingfisher eggs from the upper Hudson River basin, New York, USA
Nesting belted kingfishers (hereafter kingfishers, Ceryle alcyon) were studied on the Hudson River near Fort Edward south to New Baltimore (NY, USA) and three nearby river drainages in 2004. Concentrations of 28 organochlorine pesticides, 160 polychlorinated biphenyl (PCB) congeners, and 17 dioxin and furan (PCDD‐F) congeners were quantified in kingfisher eggs. The pattern of organochlorine pesticAuthorsThomas W. Custer, Christine M. Custer, Brian R. GrayAssociations between land use and Perkinsus marinus infection of eastern oysters in a high salinity, partially urbanized estuary
Infection levels of eastern oysters by the unicellular pathogen Perkinsus marinus have been associated with anthropogenic influences in laboratory studies. However, these relationships have been difficult to investigate in the field because anthropogenic inputs are often associated with natural influences such as freshwater inflow, which can also affect infection levels. We addressed P. marinus-laAuthorsBrian R. Gray, David Bushek, J. Wanzer Drane, Dwayne PorterAn empirical study of statistical properties of variance partition coefficients for multi-level logistic regression models
Partitioning the variance of a response by design levels is challenging for binomial and other discrete outcomes. Goldstein (2003) proposed four definitions for variance partitioning coefficients (VPC) under a two-level logistic regression model. In this study, we explicitly derived formulae for multi-level logistic regression model and subsequently studied the distributional properties of the calAuthorsJi Li, B. R. Gray, D.M. BatesEffects of methylmercury exposure on the immune function of juvenile common loons (Gavia immer)
We conducted a dose-response laboratory study to quantify the level of exposure to dietary Hg, delivered as methylmercury chloride (CH3HgCl), that is associated with suppressed immune function in captive-reared common loon (Gavia immer) chicks. We used the phytohemagglutinin (PHA) skin test to assess T-lymphocyte function and the sheep red blood cell (SRBC) hemagglutination test to measure antibodAuthorsK.P. Kenow, K.A. Grasman, R. K. Hines, M.W. Meyer, A. Gendron-Fitzpatrick, M. G. Spalding, B. R. GrayPower to detect trend in short-term time series of bird abundance
Avian point counts for population monitoring are often collected over a short timespan (e.g., 3-5 years). We examined whether power was adequate (power ???0.80) in short-duration studies to warrant the calculation of trend estimates. We modeled power to detect trends in abundance indices of eight bird species occurring across three floodplain habitats (wet prairie, early successional forest, and mAuthorsW.E. Thogmartin, B. R. Gray, M. Gallagher, N. Young, J.J. Rohweder, M. G. KnutsonEstimating trend precision and power to detect trends across grouped count data
Ecologists commonly use grouped or clustered count data to estimate temporal trends in counts, abundance indices, or abundance. For example, the U.S. Breeding Bird Survey data represent multiple counts of birds from within each of multiple, spatially defined routes. Despite a reliance on grouped counts, analytical methods for prospectively estimating precision of trend estimates or statistical powAuthorsB. R. Gray, M.M. BurlewBreeding bird territory placement in riparian wet meadows in relation to invasive reed canary grass, Phalaris arundinacea
Invasive plants are a growing concern worldwide for conservation of native habitats. In endangered wet meadow habitat in the Upper Midwestern United States, reed canary grass (Phalaris arundinacea) is a recognized problem and its prevalence is more widespread than the better-known invasive wetland plant purple loosestrife (Lythrum salicaria). Although resource managers are concerned about the effeAuthorsE.M. Kirsch, B. R. Gray, T.J. Fox, W.E. ThogmartinChlorophyll a and inorganic suspended solids in backwaters of the upper Mississippi River system: Backwater lake effects and their associations with selected environmental predictors
The Long Term Resource Monitoring Program (LTRMP) uses a stratified random sampling design to obtain water quality statistics within selected study reaches of the Upper Mississippi River System (UMRS). LTRMP sampling strata are based on aquatic area types generally found in large rivers (e.g., main channel, side channel, backwater, and impounded areas). For hydrologically well-mixed strata (i.e.,AuthorsJames T. Rogala, Brian R. GraySelecting a distributional assumption for modelling relative densities of benthic macroinvertebrates
The selection of a distributional assumption suitable for modelling macroinvertebrate density data is typically challenging. Macroinvertebrate data often exhibit substantially larger variances than expected under a standard count assumption, that of the Poisson distribution. Such overdispersion may derive from multiple sources, including heterogeneity of habitat (historically and spatially), diffeAuthorsB. R. GrayModelling habitat associations with fingernail clam (Family: Sphaeriidae) counts at multiple spatial scales using hierarchical count models
1. Macroinvertebrate count data often exhibit nested or hierarchical structure. Examples include multiple measurements along each of a set of streams, and multiple synoptic measurements from each of a set of ponds. With data exhibiting hierarchical structure, outcomes at both sampling (e.g. within stream) and aggregated (e.g. stream) scales are often of interest. Unfortunately, methods for modelliAuthorsBrian R. Gray, Roger J. Haro, James T. Rogala, Jennifer S. SauerAgricultural ponds support amphibian populations
In some agricultural regions, natural wetlands are scarce, and constructed agricultural ponds may represent important alternative breeding habitats for amphibians. Properly managed, these agricultural ponds may effectively increase the total amount of breeding habitat and help to sustain populations. We studied small, constructed agricultural ponds in southeastern Minnesota to assess their value aAuthorsM. G. Knutson, W. B. Richardson, D.M. Reineke, B. R. Gray, J.R. Parmelee, S.E. WeickFlow cytometry used to assess genetic damage in frogs from farm ponds
Flow cytometry (FC) is a laboratory method used to detect genetic damage induced by environmental contaminants and other stressors in animals, including amphibians. We tested FC methods on three species of ranid frogs collected from farm ponds and natural wetlands in southeastern Minnesota. We compared FC metrics for Rana clamitans between ponds with direct exposure to agricultural contaminants anAuthorsB.L. Bly, M. G. Knutson, M.B. Sandheinrich, B. R. Gray, D.A. Jobe - Software