William Link, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 44
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Filter Total Items: 122
Efficient implementation of the Metropolis-Hastings algorithm, with application to the Cormack-Jolly-Seber model
Judicious choice of candidate generating distributions improves efficiency of the Metropolis-Hastings algorithm. In Bayesian applications, it is sometimes possible to identify an approximation to the target posterior distribution; this approximate posterior distribution is a good choice for candidate generation. These observations are applied to analysis of the Cormack-Jolly-Seber model and its ex
Authors
W. A. Link, R. J. Barker
Bayesian multimodel inference for dose-response studies
Statistical inference in dose-response studies is model-based: The analyst posits a mathematical model of the relation between exposure and response, estimates parameters of the model, and reports conclusions conditional on the model. Such analyses rarely include any accounting for the uncertainties associated with model selection. The Bayesian inferential system provides a convenient framework fo
Authors
W. A. Link, P.H. Albers
Stable isotope and pen feeding trial studies confirm the value of horseshoe crab Limulus polyphemus eggs to spring migrant shorebirds in Delaware Bay
We used stable isotope (SI) methods in combination with pen feeding trials to determine the importance of eggs of the Atlantic horseshoe crab Limulus polyphemus to migratory fattening of red knots Calidris canutus rufa and ruddy turnstones Arenaria interpres morinella during spring stopover in Delaware Bay. By manifesting measurable fractionation (ca +3‰) and rapid turnover, blood plasma δ15 nitro
Authors
G. M. Haramis, W. A. Link, P.C. Osenton, Daniel B. Carter, R.G. Weber, N.A. Clark, M.A. Teece, D.S. Mizrahi
Analysis of multinomial models with unknown index using data augmentation
Multinomial models with unknown index ('sample size') arise in many practical settings. In practice, Bayesian analysis of such models has proved difficult because the dimension of the parameter space is not fixed, being in some cases a function of the unknown index. We describe a data augmentation approach to the analysis of this class of models that provides for a generic and efficient Bayesian
Authors
J. Andrew Royle, R.M. Dorazio, W. A. Link
Effects of methylmercury on reproduction in American kestrels
Sixty breeding pairs of captive American kestrels (Falco sparverius) were exposed to a range of sublethal dietary concentrations of mercury (Hg), in the form of methylmercuric chloride, and their subsequent reproduction was measured. Egg production, incubation performance, and the number and percent of eggs hatched decreased markedly between 3.3 and 4.6 mg/kg dry weight of Hg (1.2 and 1.7 mg/kg we
Authors
P.H. Albers, M.T. Koterba, R. Rossmann, W. A. Link, J.B. French, R.S. Bennett, W.C. Bauer
Seasonal components of avian population change: Joint analysis of two large-scale monitoring programs
We present a combined analysis of data from two large-scale surveys of bird populations. The North American Breeding Bird Survey is conducted each summer; the Christmas Bird Count is conducted in early winter. The temporal staggering of these surveys allows investigation of seasonal components of population change, which we illustrate with an examination of the effects of severe winters on the Car
Authors
W. A. Link, J.R. Sauer
A hierarchical model for regional analysis of population change using Christmas Bird Count data, with application to the American Black Duck
Analysis of Christmas Bird Count (CBC) data is complicated by the need to account for variation in effort on counts and to provide summaries over large geographic regions. We describe a hierarchical model for analysis of population change using CBC data that addresses these needs. The effect of effort is modeled parametrically, with parameter values varying among strata as identically distribute
Authors
W. A. Link, J.R. Sauer, D.K. Niven
Effects of methyl mercury on reproduction in American kestrels
Methyl mercury (MeHg) readily passes through biological membranes, accumulates in individuals, and biomagnifies in higher order predators. It is acutely toxic to some birds at 5-15 parts per million (ppm) wet weight in the diet, and it can damage the central nervous system, impair reproduction, and retard growth and development. The effects of MeHg on reproduction in wild raptors are poorly know
Authors
P.H. Albers, M.T. Koterba, R. Rossmann, J.B. French, R.S. Bennett, W.C. Bauer, W. A. Link
Model weights and the foundations of multimodel inference
Statistical thinking in wildlife biology and ecology has been profoundly influenced by the introduction of AIC (Akaike?s information criterion) as a tool for model selection and as a basis for model averaging. In this paper, we advocate the Bayesian paradigm as a broader framework for multimodel inference, one in which model averaging and model selection are naturally linked, and in which the per
Authors
W. A. Link, R. J. Barker
Toxicity and hazard of vanadium to mallard ducks (Anas platyrhynchos) and Canada geese (Branta canadensis)
A recent Canada goose (Branta canadensis) die-off at a petroleum refinery fly ash pond in Delaware was attributed to vanadium (V) toxicity. Because of the paucity of V toxicity data for wild birds, a series of studies was undertaken using the forms of V believed to have resulted in this incident. In 7-d single oral dose trials with mallard drakes (Anas platyrhynchos), the estimated median lethal d
Authors
Barnett A. Rattner, Moira A. McKernan, Karen M. Eisenreich, William A. Link, Glenn H. Olsen, David J. Hoffman, K.A. Knowles, Peter C. McGowan
Generalized site occupancy models allowing for false positive and false negative errors
Site occupancy models have been developed that allow for imperfect species detection or ?false negative? observations. Such models have become widely adopted in surveys of many taxa. The most fundamental assumption underlying these models is that ?false positive? errors are not possible. That is, one cannot detect a species where it does not occur. However, such errors are possible in many samp
Authors
J. Andrew Royle, W. A. Link
Science and Products
Filter Total Items: 44
No results found.
Filter Total Items: 122
Efficient implementation of the Metropolis-Hastings algorithm, with application to the Cormack-Jolly-Seber model
Judicious choice of candidate generating distributions improves efficiency of the Metropolis-Hastings algorithm. In Bayesian applications, it is sometimes possible to identify an approximation to the target posterior distribution; this approximate posterior distribution is a good choice for candidate generation. These observations are applied to analysis of the Cormack-Jolly-Seber model and its ex
Authors
W. A. Link, R. J. Barker
Bayesian multimodel inference for dose-response studies
Statistical inference in dose-response studies is model-based: The analyst posits a mathematical model of the relation between exposure and response, estimates parameters of the model, and reports conclusions conditional on the model. Such analyses rarely include any accounting for the uncertainties associated with model selection. The Bayesian inferential system provides a convenient framework fo
Authors
W. A. Link, P.H. Albers
Stable isotope and pen feeding trial studies confirm the value of horseshoe crab Limulus polyphemus eggs to spring migrant shorebirds in Delaware Bay
We used stable isotope (SI) methods in combination with pen feeding trials to determine the importance of eggs of the Atlantic horseshoe crab Limulus polyphemus to migratory fattening of red knots Calidris canutus rufa and ruddy turnstones Arenaria interpres morinella during spring stopover in Delaware Bay. By manifesting measurable fractionation (ca +3‰) and rapid turnover, blood plasma δ15 nitro
Authors
G. M. Haramis, W. A. Link, P.C. Osenton, Daniel B. Carter, R.G. Weber, N.A. Clark, M.A. Teece, D.S. Mizrahi
Analysis of multinomial models with unknown index using data augmentation
Multinomial models with unknown index ('sample size') arise in many practical settings. In practice, Bayesian analysis of such models has proved difficult because the dimension of the parameter space is not fixed, being in some cases a function of the unknown index. We describe a data augmentation approach to the analysis of this class of models that provides for a generic and efficient Bayesian
Authors
J. Andrew Royle, R.M. Dorazio, W. A. Link
Effects of methylmercury on reproduction in American kestrels
Sixty breeding pairs of captive American kestrels (Falco sparverius) were exposed to a range of sublethal dietary concentrations of mercury (Hg), in the form of methylmercuric chloride, and their subsequent reproduction was measured. Egg production, incubation performance, and the number and percent of eggs hatched decreased markedly between 3.3 and 4.6 mg/kg dry weight of Hg (1.2 and 1.7 mg/kg we
Authors
P.H. Albers, M.T. Koterba, R. Rossmann, W. A. Link, J.B. French, R.S. Bennett, W.C. Bauer
Seasonal components of avian population change: Joint analysis of two large-scale monitoring programs
We present a combined analysis of data from two large-scale surveys of bird populations. The North American Breeding Bird Survey is conducted each summer; the Christmas Bird Count is conducted in early winter. The temporal staggering of these surveys allows investigation of seasonal components of population change, which we illustrate with an examination of the effects of severe winters on the Car
Authors
W. A. Link, J.R. Sauer
A hierarchical model for regional analysis of population change using Christmas Bird Count data, with application to the American Black Duck
Analysis of Christmas Bird Count (CBC) data is complicated by the need to account for variation in effort on counts and to provide summaries over large geographic regions. We describe a hierarchical model for analysis of population change using CBC data that addresses these needs. The effect of effort is modeled parametrically, with parameter values varying among strata as identically distribute
Authors
W. A. Link, J.R. Sauer, D.K. Niven
Effects of methyl mercury on reproduction in American kestrels
Methyl mercury (MeHg) readily passes through biological membranes, accumulates in individuals, and biomagnifies in higher order predators. It is acutely toxic to some birds at 5-15 parts per million (ppm) wet weight in the diet, and it can damage the central nervous system, impair reproduction, and retard growth and development. The effects of MeHg on reproduction in wild raptors are poorly know
Authors
P.H. Albers, M.T. Koterba, R. Rossmann, J.B. French, R.S. Bennett, W.C. Bauer, W. A. Link
Model weights and the foundations of multimodel inference
Statistical thinking in wildlife biology and ecology has been profoundly influenced by the introduction of AIC (Akaike?s information criterion) as a tool for model selection and as a basis for model averaging. In this paper, we advocate the Bayesian paradigm as a broader framework for multimodel inference, one in which model averaging and model selection are naturally linked, and in which the per
Authors
W. A. Link, R. J. Barker
Toxicity and hazard of vanadium to mallard ducks (Anas platyrhynchos) and Canada geese (Branta canadensis)
A recent Canada goose (Branta canadensis) die-off at a petroleum refinery fly ash pond in Delaware was attributed to vanadium (V) toxicity. Because of the paucity of V toxicity data for wild birds, a series of studies was undertaken using the forms of V believed to have resulted in this incident. In 7-d single oral dose trials with mallard drakes (Anas platyrhynchos), the estimated median lethal d
Authors
Barnett A. Rattner, Moira A. McKernan, Karen M. Eisenreich, William A. Link, Glenn H. Olsen, David J. Hoffman, K.A. Knowles, Peter C. McGowan
Generalized site occupancy models allowing for false positive and false negative errors
Site occupancy models have been developed that allow for imperfect species detection or ?false negative? observations. Such models have become widely adopted in surveys of many taxa. The most fundamental assumption underlying these models is that ?false positive? errors are not possible. That is, one cannot detect a species where it does not occur. However, such errors are possible in many samp
Authors
J. Andrew Royle, W. A. Link