Thesis (Ph.D.)--University of Iowa, 2006. / Supervisor: Frank H. Weirich. Includes bibliographical references (leaves 152-160)

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains vii, 90 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references (p. 78-85).

Thesis (M. Agr. Sc.)--Lincoln University, 1992. / Also available via the World Wide Web.

Grassland organisms evolved alongside the interaction of fire and grazing, but modern management often decouples these disturbances. In order to analyze the effects of reintroducing this interaction, we implemented four treatments. Two of these treatments were variations of patch-burn grazing, one was modified rest-rotation grazing, and one was season-long grazing. We chose to monitor the butterfly response to these treatments because butterflies have short generations, require a wide variety of resources, and are easily identifiable as adults. We quantified both the butterfly community and the behavioral time budgets of two species. We found that the butterfly community is more species-rich and abundant in treatments including fire than in treatments without fire. We found no difference in time budgets between treatments. Overall, we suggest that managers implement a carefully-planned patch-burn grazing regime in order to support grassland butterflies and other organisms.

Tree diameter, bark thickness and texture, litter bulk density and chemistry, and sprouting ability are a few, species-specific adaptations and properties that may be related to an individual tree stem's potential fire resistance. Based upon these features and others, trees exhibiting similar characteristics have been broadly classified as pyrophytic or pyrophobic. To our knowledge, few if any, research studies have been conducted to determine if tree buds may exhibit speciesspecific fire or heat tolerance. Understanding potential relationships between bud characteristics and fire tolerance may assist prescribed fire managers as they target control of specific undesired tree species while promoting desired tree species. Buds of six common hardwood species in the southeastern U.S. were harvested and exposed to different heat dosages using a propane gas tube burner: red maple (Acer rubrum L.), yellow-poplar (Liriodendron tulipifera L.), American beech (Fagus grandifolia Ehrh.), mockernut hickory (Carya tomentosa Lam.), scarlet oak (Quercus coccinea Münchh.), and chestnut oak (Quercus montana Willd.). These species are commonly categorized as pyrophobic (American beech, red maple, yellow-poplar) and pyrophytic (chestnut oak, mockernut hickory, scarlet oak). Using electrolyte leakage of heated and unheated buds, the mean difference in bud percent mortality between heated and unheated buds was compared by species, functional group, and differing heat dosages. The mean difference in bud percent mortality differed between the heated and unheated buds by species (p < 0.0001). Heated buds of yellow-poplar, mockernut hickory, and chestnut oak displayed similar percent mortality; however, the presumed pyrophytic species had greater heated bud percent mortality (34.0 %) than the pyrophobic species (26.8 %) (p = 0.0003). Heated bud percent mortality differed based upon differing heat dosage levels (height above the propane burner and heat exposure time) and their species-specific interactions. Fire tolerance, as assigned and assessed by features such as bark texture and thickness, may not be directly related to mid-story tree bud physical properties (i.e. length, mass, and diameter) or fire tolerance. Research including additional species, heat dosages, and different sampling times (i.e. late fall vs. late winter) would be valuable for investigating these dynamics further. Deploying a similar, field-scale experiment before and after prescribed burns would be useful to determine how tree buds may respond to different heat dosages that could be exacted during prescribed burns. / Master of Science / Prescribed fire is utilized on millions of acres per year in the southeastern United States. These burns are conducted for a variety of reasons, including: wildlife habitat establishment, restoration, and maintenance; aesthetics; hazardous fuel reduction; and the control of undesired vegetative species. Factors that may influence an individual species' response to fire include, but are not limited to: bark thickness and texture, litter bulk density and chemistry, and resprouting strategy. These traits may differ by species and by the age of a given stem. Few studies have investigated these characteristics in younger tree stems within the southeastern United States. Additionally, few research studies in any ecosystem have investigated potential species-specific tree bud responses to increased heat. Determining if undesired tree species respond differently to heating than desired tree species may provide additional information to assist prescribed fire managers in many locations where vegetation control is a management objective. As a result of this knowledge gap, a research study was designed to investigate these dynamics in the southeastern United States for six common, hardwood tree species: red maple (Acer rubrum L.), yellow-poplar (Liriodendron tulipifera L.), American beech (Fagus grandifolia Ehrh.), mockernut hickory (Carya tomentosa Lam.), scarlet oak (Quercus coccinea Münchh.), and chestnut oak (Quercus montana Willd.). The results suggested that percent bud mortality may be species-specific, but few relationships appeared to be present to relate bud physical characteristics to bud mortality. Additionally, supposed heat tolerance groups assigned to older tree stems based upon traits, such as bark thickness and texture, did not provide a valid assessment of bud mortality. Additional research is needed to understand these dynamics further, including burning under different heat dosages, evaluating additional tree species, and assessing bud mortality resulting from in-the-field prescribed fires.

Thesis(M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographic references (p.64-82).

Thesis (M.S.)--Oregon State University, 1995. / Typescript (photocopy). Includes bibliographical references (leaves 53-54). Also available on the World Wide Web.

Thesis (M.A.)--Humboldt State University, 2009. / Includes bibliographical references (leaves 94-98). Also available via Humboldt Digital Scholar.

In ultra-deep submicron VLSI designs, clock network layout plays an increasingly important role in determining circuit performance including timing, power consumption, cost, power supply noise and tolerance to process variations. It is required that a clock layout algorithm can achieve any prescribed skews with the minimum wire length and acceptable slew rate. Traditional zero-skew clock routing methods are not adequate to address this demand, since they tend to yield excessive wire length for prescribed skew targets. The interactions among skew targets, sink location proximities and capacitive load balance are analyzed. Based on this analysis, a maximum delay-target ordering merging scheme is suggested to minimize wire and buffer area, which results in lesser cost, power consumption and vulnerability to process variations. During the clock routing, buffers are inserted simultaneously to facilitate a proper slew rate level and reduce wire snaking. The proposed algorithm is simple and fast for practical applications. Experimental results on benchmark circuits show that the algorithm can reduce the total wire and buffer capacitance by 60% over an extension of the existing zero-skew routing method.

In ultra-deep submicron VLSI designs, clock network layout plays an increasingly important role in determining circuit performance including timing, power consumption, cost, power supply noise and tolerance to process variations. It is required that a clock layout algorithm can achieve any prescribed skews with the minimum wire length and acceptable slew rate. Traditional zero-skew clock routing methods are not adequate to address this demand, since they tend to yield excessive wire length for prescribed skew targets. The interactions among skew targets, sink location proximities and capacitive load balance are analyzed. Based on this analysis, a maximum delay-target ordering merging scheme is suggested to minimize wire and bu&#64256;er area, which results in lesser cost, power consumption and vulnerability to process variations. During the clock routing, bu&#64256;ers are inserted simultaneously to facilitate a proper slew rate level and reduce wire snaking. The proposed algorithm is simple and fast for practical applications. Experimental results on benchmark circuits show that the algorithm can reduce the total wire and bu&#64256;er capacitance by 60% over an extension of the existing zero-skew routing method.