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Showing 1 to 20 of 23 for “"group-selection"”.
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Group Selection in Semiparametric and Nonparametric Accelerated Failure Time Models
… outcome. When covariates can be naturally grouped, group selection is important in these models. Motivated by the group bridge approach for variable selection in a multiple linear regression model, we consider group selection in a semiparametric accelerated failure time (AFT) model using …
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Development of a method for implementing group selection in Appalachian hardwoods
A method is described for implementing group selection regeneration in Appalachian hardwoods. The diverse set of definitions of the method, and the current forest demands are combined to form a flexible system of implementation that can accommodate public as well as private forests. Group selection …
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Effects of group selection and clearcut openings on wildlife in Appalachian hardwood forests
Group selection has recently emerged as an alternative silvicultural system to clearcutting in Appalachian hardwood forests, but there is little, if any, information on the effects of group selection on wildlife. Thus, I studied and compared the effects of group selection and clearcut openings on …
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The impact of group selection silviculture on timber harvesting cost in the southern Appalachians
… and clearcutting to uneven-aged management and group selection silviculture. Group selection, with its small 1/2-to-2-acre patch cuts widely dispersed throughout a timber stand, has the potential to substantially increase timber harvesting costs over traditional clearcutting. This could …
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Impacts of group selection harvest openings on the reproductive success of the Solitary Vireo (Vireo solitarius alticola)
… in 1994 and on three sites harvested using the group selection method in 1995. Pairing success was 88% on the unharvested site in 1994, however it was lower on the harvested sites in 1995 (53.8%). Low reproductive success was observed in both years (12% and 22% respectively). In 1995, the amount …
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Influences of varying stand harvest methods on timber harvesting costs in southwestern Virginia hardwoods
… operation to estimate the cost of harvesting a group selection tract as compared to a clearcut. Eight loggers were contacted and interviewed to obtain data on their costs of logging. The mean, median, and standard deviation of the responses were calculated to develop a profile. Mean crew size …
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Effects of alternative silvicultural practices on oak regeneration in the southern Appalachians
… commercial clearcut, shelterwood, and group selection. The effects of harvesting were compared among sites and among treatments. Oak regeneration dominance, measured by the relative density of dominant and codominant oak regeneration, was the most important variable calculated from the …
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Vegetation Responses to Seven Silvicultural Treatments in the Southern Appalachians One-Year After Harvesting
… control, 2) understory control by herbicide, 3) group selection, 4) high-leave shelterwood, 5) low-leave shelterwood, 6) leave tree, and 7) clearcut. The effects of harvesting were compared between treatments and between pre-harvest and post-harvest samplings. Species richness, percent cover, and …
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Habitat Relationships of Breeding Birds in Bottomland Hardwood Forests of the Altamaha River, Georgia
… active management. However, single-tree or group-selection harvests may be beneficial to a few important breeding Neotropical migratory bird species.
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Collective and Individual Rationality: Some Episodes in the History of Economic Thought
… here as being based on the exploded notion of group selection, cannot underpin the desirability of spontaneous outcomes. I conclude by arguing that Keynes shares the holistic approach of Smith and Hayek, but without their reliance on invisible hand mechanisms. If spontaneous processes cannot be …
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Economic behavior from an evolutionary perspective
… show that risk aversion emerges via natural selection if reproductive risk is "systematic", i.e., correlated across individuals in a given generation. The degree of risk aversion is determined by the stochastic nature of reproductive rates, and different statistical properties lead to …
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The impacts of seven silvicultural alternatives on vascular plant community composition, structure, and diversity in the southern Appalachians
… (2) understory control with herbicide, (3) group selection, (4) high-leave shelterwood, (5) low-leave shelterwood, (6) leave tree, and (7) clearcut. The effects of each treatment on the vascular plant community were characterized by changes in species diversity, species composition, exotic …
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Organizing for Change: An Assessment of Organization Development Activities of Training Consultants
… the number and percentage of total response group selection. Tables and charts with numerical summaries were used to augment the written description of the results. The findings of the study demonstrate that the field of organization development must come to grips with its fragmented rather …
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A Study to Determine the Impact of a Precollege Intervention Program on Early Adolescent Aspiration and Motivation for College in West Virginia
… 265 (88%) who responded were divided into two groups: a participant group consisting of 104 students who participated in the 1996 program and a comparison group consisting of 161 students who did not attend the 1996 program. T-tests and chi square tests revealed no significant differences …
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Conceptual Challenges in Cultural Selection
… key conceptual challenges within cultural selection, in order to provide a rigorous evaluation of its promise and scope. Cultural selection, a process analogous to natural selection which operates on cultural traits, has been proposed as an explanation for a wide range of phenomena. These …
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Effects of Alternative Silvicultural Treatments on Regeneration in the Southern Appalachians
… commercial harvest, leave-tree, shelterwood, group selection, midstory treatment, and an uncut control. The second only focused on the clearcut, leave-tree, and shelterwood. These treatments were implemented in seven stands in Virginia and West Virginia over two physiographic provinces, the …
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Innovative Methods for the Design and Analysis of Phase II Clinical Trials
… terms of dose-ranging study, patient population selection, and decentralized clinical trials (DCTs). This dissertation presents a comprehensive set of methodologies that address these critical issues with three projects. The first project introduces a Bayesian adaptive dose-ranging design that …
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