James H. Roberds

Works (11)

Updated: July 15th, 2023 21:15

2004 journal article

On-bark behavior of Dendroctonus frontalis: a Markov chain analysis

JOURNAL OF INSECT BEHAVIOR, 17(3), 281–301.

By: J. Bishir n, J. Roberds* & B. Strom*

author keywords: Scolytidae; southern pine beetle; host selection; host recognition; transition probabilities; absorbing states
TL;DR: This work applied Markov chain analysis to on-bark behaviors of the southern pine beetle, Dendroctonus frontalis Zimmermann, and found that by developing chains for each sex, sexually dichotomous fighting behaviors were revealed. (via Semantic Scholar)
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13. Climate Action (Web of Science)
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Source: Web Of Science
Added: August 6, 2018

2001 journal article

On the structure of attractors for discrete, periodically forced systems with applications to population models

PHYSICA D, 158(1-4), 69–82.

By: J. Selgrade n & J. Roberds*

author keywords: periodic forcing; attractors; discrete population models
TL;DR: A method is presented which shows that if the amplitude of the k-periodic forcing is small enough then the attractor for the forced system is the union of k homeomorphic subsets. (via Semantic Scholar)
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Source: Web Of Science
Added: August 6, 2018

2000 journal article

Dynamical analysis of density-dependent selection in a discrete one-island migration model

MATHEMATICAL BIOSCIENCES, 164(1), 1–15.

By: J. Roberds* & J. Selgrade n

author keywords: selection; migration; genotype; density-dependence; bifurcation
MeSH headings : Alleles; Animals; Emigration and Immigration; Genetic Variation / genetics; Geography; Humans; Models, Genetic; Nonlinear Dynamics; Polymorphism, Genetic / genetics; Population Dynamics; Selection, Genetic
TL;DR: A system of non-linear difference equations is used to model the effects of density-dependent selection and migration in a population characterized by two alleles at a single gene locus, and properties for a genetically important class of equilibria associated with complete dominance in fitness are described. (via Semantic Scholar)
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Source: Web Of Science
Added: August 6, 2018

1998 journal article

Genetic variance in the F-2 generation of divergently selected parents

THEORETICAL AND APPLIED GENETICS, 97(5-6), 990–993.

By: M. Koshy*, G. Namkoong* & J. Roberds n

author keywords: F-2 genetic variance; divergent selection; provenance hybrids
TL;DR: The size of the genetic variance to the population divergence is related based on a forward and backward mutation model at a locus with two alleles with additive gene action at a region with high population divergence. (via Semantic Scholar)
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13. Climate Action (Web of Science)
15. Life on Land (Web of Science)
Source: Web Of Science
Added: August 6, 2018

1997 journal article

Genotype by environment interaction for index traits that combine growth and wood density in loblolly pine

THEORETICAL AND APPLIED GENETICS, 94(8), 1015–1022.

By: S. McKeand n , G. Eriksson * & J. Roberds*

author keywords: gain; K-statistic; Pinus taeda L; selection index; stability; tree improvement
TL;DR: The interaction variance of an index trait is shown to be a function of the index coefficients and the G×E variances and covariances for its constituent traits, and for some conditions it surpasses the magnitude of G–E variance for each component trait. (via Semantic Scholar)
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13. Climate Action (Web of Science)
15. Life on Land (Web of Science)
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

1997 journal article

Limit theorems and a general framework for risk analysis in clonal forestry

MATHEMATICAL BIOSCIENCES, 142(1), 1–11.

By: J. Bishir n & J. Roberds n

MeSH headings : Forestry / statistics & numerical data; Mathematics; Models, Biological; Risk; Trees / genetics; Trees / growth & development
TL;DR: It is shown that the proportion S converges in distribution and that, under general conditions, a moderate number of clones, usually no more than 20 to 40 and often fewer, provides equivalent or better protection against catastrophic loss than does a large number of clone. (via Semantic Scholar)
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2. Zero Hunger (Web of Science)
13. Climate Action (Web of Science)
15. Life on Land (OpenAlex)
Source: Web Of Science
Added: August 6, 2018

1997 journal article

Period-doubling bifurcations for systems of difference equations and applications to models in population biology

NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS, 29(2), 185–199.

By: J. Selgrade n & J. Roberds n

author keywords: discrete models; period-doubling bifurcation; Henon map; population genetics; pioneer and climax populations
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Added: August 6, 2018

1997 article

Risk analyses in clonal forestry

Roberds, J. H., & Bishir, J. W. (1997, March). CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE, Vol. 27, pp. 425–432.

By: J. Roberds* & J. Bishir*

TL;DR: Alternative models and methods that have been proposed to investigate the effect of number of clones on risk of plantation failure following an unforeseen catastrophic event indicate that use of 30 to 40 unrelated clones in plantations provides protection against catastrophic failure roughly equivalent to the use of large numbers of unrelated clones. (via Semantic Scholar)
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2. Zero Hunger (Web of Science)
13. Climate Action (Web of Science)
Source: Web Of Science
Added: August 6, 2018

1991 journal article

EFFECTIVE NUMBER OF POLLEN PARENTS IN CLONAL SEED ORCHARDS

THEORETICAL AND APPLIED GENETICS, 82(3), 313–320.

By: J. Roberds n, S. Friedman* & Y. Elkassaby

author keywords: VARIANCE EFFECTIVE NUMBER; TEMPORAL METHOD; GENE FREQUENCY VARIANCE; GENETIC DRIFT; MALE GAMETE POPULATIONS
TL;DR: The estimation of effective numbers of pollen parents from seed samples collected from individual ramets in clonal seed orchards of forest tree species is presented, which are variance effective numbers for populations of male gametes that are successful in uniting with ovules to produce viable seed. (via Semantic Scholar)
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UN Sustainable Development Goal Categories
15. Life on Land (Web of Science)
Source: Web Of Science
Added: August 6, 2018

1990 journal article

Genetic analysis of risk in clonal populations of forest trees

Theoretical and Applied Genetics, 79(6), 841.

By: J. Roberds, G. Namkoong & T. Skroppa

Source: NC State University Libraries
Added: August 6, 2018

1990 journal article

Height response functions for white ash provenances grown at different latitudes

Silvae Genetica, 39(3-4), 121.

By: J. Roberds, J. Hyun, G. Namkoong & G. Rink

Source: NC State University Libraries
Added: August 6, 2018

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