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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Biomimicry of the Manduca sexta Hawkmoth in Artificial Wings for use in a Flapping Wing Micro Aerial Vehicle

Weisfeld, Matthias 23 May 2019 (has links)
No description available.
182

The diversity of moths in a nature reserve in the Northern Cape, South Africa : Variation over time, depending on abiotic factors and differences between areas with different grazing types

Jarl, Nellie January 2023 (has links)
Land use changes globally have significant impacts on flora and fauna. In South Africa, extensive land is used for grazing by both domestic livestock and farmed native grazers. However, the effects of different grazing types on vegetation and fauna remain poorly understood. The Northern Cape, the country's largest province with a substantial agricultural sector, lacks comprehensive insect research. This study aimed to investigate moth diversity in an unstudied area, assessing species composition, dung beetle abundance, vegetational patterns, and the influence of abiotic factors and trap types on catches of moth in areas with varying grazing practices. Habitat types and habitat preferences were also examined. The research was conducted in the mid-north region of the Kalahari, Northern Cape province, between February and April 2023. Moths were captured using three different light sources, three times a week, and a subset of moths were counted and registered. The findings revealed the presence of at least 142 macromoth morphospecies, with higher abundance and species richness in areas grazed by domestic animals compared to native grazers. Dung beetle abundance was also greater in these areas. Notably, different habitats exhibited variations in moth occurrence, with specific morphospecies showing preferences for particular habitats. Plant species richness was higher in areas grazed by native grazers, while vegetational cover was greater in areas grazed by domestic animals. The study could show influence of moonlight, temperature, and windspeed on moth catches, and trap types affected the number of morphospecies captured. Surprisingly, the results contradict previous studies that suggested higher diversity in areas grazed by native grazers. Possible explanations include differences between the two areas in how beneficial the surrounding areas are, differences in abiotic factors, environmental productivity, habitat heterogeneity and plant species composition. Further studies of differences between areas with different grazing types in similar regions are needed to validate the findings of this study.
183

An Ethnographic Study of The Moth Detroit StorySLAM

Janssen, Catherine Jo 15 August 2012 (has links) (PDF)
The Moth Detroit StorySLAM is one of many storytelling events staged in urban bar environments. Unlike the increasingly aged audiences attending the National Storytelling Festival and similar story festivals, the Detroit StorySLAM consistently yields at capacity crowds of college students and young professionals. Participants were informally interviewed during the September, October, and November slams of 2010 and the January 2011 slam. In addition to conducting these interviews, the researcher was a participant observer—throwing her name into the hat and being twice called to the stage. Data are presented as a thick description organized according to Richard Bauman's 6 situational factors of the performance event. Until now questions about the nature and meaning of storytelling have been largely considered from the storyteller's perspective. By redirecting those questions to the listeners, this study reveals the ethos of hundreds of story enthusiasts—an undisputed admiration for the revelation of authentic, individual truths.
184

Nanofabrication Techniques for Nanophotonics

Yavuzcetin, Ozgur 01 September 2009 (has links)
This thesis reports the fabrication of nanophotonic structures by using electron beam lithography and using pattern transfer via self assembly with the aid of block copolymers. A theoretical and experimental basis was developed for fabricating anti-reflective coatings using block-copolymer pattern transfer. Block-copolymers were also used to fabricate plasmonic pattern arrays which form gold dots on glass surface. Electron-beam lithography was utilized to fabricate holey plasmonic structures from gold and silver films. Electron-beam exposure was used in block-copolymer lithography in selected regions. The exposure effects were studied for both thin and thick block-copolymer films. Reactive and ion beam etching techniques were used and optimized to fabricate those structures. This research required a great deal of development of new fabrication methods and key information is included in the body of the thesis.
185

THE IMPACT OF INSECT DEFOLIATION ON CARBON FLUXES IN A TEMPERATE DECIDUOUS FOREST / THE IMPACT OF INSECT DEFOLIATION ON A DECEDIOUS FOREST

Latifovic, Lejla January 2023 (has links)
Temperate forests are an important global carbon sink. However, various environmental disturbances can impact carbon sequestration capabilities of these forests. In 2021, a record-breaking defoliation, caused by the spongy moth (Lymantria dispar L., formerly knows as the gypsy moth) occurred in eastern North America. In this study, we assess the impact of this spongy moth defoliation on carbon uptake in a mature oak-dominated temperate forest in the Great Lakes region in Canada, using eddy covariance flux data from 2012 to 2022. The forest is more than 90 years old and known as CA-TPD site in the AmeriFlux and global FLUXNET networks. Study results showed that prior to spongy moth defoliation the forest was a carbon sink with mean annual gross ecosystem productivity (GEP) of 1,367 ± 104, ecosystem respiration (RE) of 1,201 ± 145 and, net ecosystem productivity (NEP) of 197 ± 74 g C m−2 yr−1 over the 2012–2020 period. However, due the defoliation in the early growing season in 2021, GEP declined to 959 g C m-2 yr-1 and RE increased to 1,345 g C m-2 yr-1 causing the forest to became a large source of carbon with annual NEP of -351 g C m-2 yr−1. This large decline in annual NEP was a result of both reduced GEP (30%) and elevated RE (12%). However, in 2022, forest carbon fluxes recovered to pre-infestation levels, with a GEP value of 1,671 g C m-2 yr-1, an RE value of 1,287 g C m-2 yr-1, and an NEP value of 298 g C m-2 yr-1, indicating that the forest was once again a large carbon sink. This research demonstrates that major transient natural disturbances such as the 2021 spongy moth defoliation can have a significant impact on forest carbon dynamics in a future warmer climate. The extent to which North American temperate forests will remain a major carbon sink will depend on the severity and intensity of these disturbance events and rate of recovery of forests following the disturbance. / Thesis / Master of Science (MSc) / Temperate deciduous forests play an important role in carbon sequestration from the atmosphere. However, the impact of climate change, extreme weather, and disturbance events can alter the extent to which these forests sequester carbon, in some cases shifting their role from being a carbon sink to becoming a carbon source to the atmosphere. In 2021, a spongy moth infestation severely defoliated a mature oak-dominated temperate forest north of Lake Erie, Ontario, Canada, turning the forest from a carbon sink to a carbon source. Our analysis indicates that meteorological conditions during the early spring might have influenced the severity of this infestation. Specifically, the prevalence of dry and warm weather conditions enabled the moth to survive and thrive longer. This study shows the significant influence of natural disturbances on forest carbon dynamics as temperatures continue to rise due to climate change. The future role forests play in carbon sequestration will be determined by the severity of disturbance events and the effectiveness of forests to recover in the aftermath of these events.
186

A BIOLOGICALLY-INSPIRED SENSOR FUSION APPROACH TO TRACKING A WIND-BORNE ODOR IN THREE DIMENSIONS

Rutkowski, Adam J. January 2008 (has links)
No description available.
187

Response of black bears to gypsy moth infestation in Shenandoah National Park, Virginia

Kasbohm, John W. 02 October 2007 (has links)
The effects of gypsy moth infestation on the Shenandoah National Park (SNP) black bear population and habitat were studied during 1985 - 1991 by comparing radio telemetry, population, and behavioral data from preinfestation years (1982 - 1986) and years with extensive defoliation (1987 - 1991). Gypsy moth defoliation (> 60% canopy loss) increased from 546 ha in 1986 (1 % of the study area), to 2,304 ha in 1987 (4%), 6,227 ha in 1988 (12%), and 17,736 ha in 1989 (34%). Chestnut oak and red oak habitat types received the greatest defoliation; 60% and 45% of these habitat types suffered greater than 60 % canopy loss in the North and Central Districts, respectively. Infestation resulted in a 99% reduction in acorn production in defoliated stands. Maximum daily temperatures 0.5 m above the ground in defoliated stands averaged 4.7 ± 0.3 C, 4.3 ± 0.4 C, and 2.5 ± 0.3 C warmer (P < 0.01) than in nondefoliated stands during peak defoliation, refoliation, and post-refoliation periods, respectively. Bear / Ph. D.
188

Modeling the impact of gypsy moth defoliation in individual tree mortality and basal area growth of northern hardwoods of central Pennsylvania

Amrhein, John Francis 22 June 2010 (has links)
Data for this study were collected by the US Forest Service and the Pennsylvania Bureau of Forestry on nearly 600 plots in central Pennsylvania. Tree and stand characteristics recorded between 1978 and 1985 include estimates of percent defoliation on individual trees. Logistic regression using maximum likelihood estimation was employed to model individual-tree mortality of 15 species in central Pennsylvania that had been defoliated by the gypsy moth. Defoliation was estimated to the nearest ten percent for individual trees. Other variables used for prediction included stand basal area and an individual-tree relative basal area index. Success ranged from no fit for three of the species to an R value (a derivation of Akaike's information criterion) of .613 for white oak. The inclusion of defoliation in the models had a varied effect. For four of the species percent defoliation was not significant. For hickory and white oak respectively, percent defoliation raised the R value by .305 and .290 percentage points. As many as five models for each species were developed: one or two models with no defoliation measure in the model and one each for one, two or three consecutive years of defoliation measures. A beta and gamma function were used to model individual· tree basal area growth for the same 15 species. The models were fit using nonlinear least squares. Variables used include the relative basal area index, stand basal area, site index and a defoliation index that incorporated three years of individual-tree, percent defoliation. The beta and gamma functions fit equally well with values of (1 - relative mean square error) ranging from .1967 to .6290. Results for both models are presented for each species. The defoliation index was a significant variable for five of the fifteen species: white, chestnut, red, and black oak and sassafras. / Master of Science
189

Effects of gypsy moth defoliation on acorn production and viability, litterfall, and litter layer depth and biomass in north-central Virginia and western Maryland

McConnell, Steven P. 20 November 2012 (has links)
The effects of gypsy moth defoliation on acorn production (the seed source for oak regeneration), and the forest floor regeneration environment were investigated. Parameters measured included: acorn quantity, weight, development, and viability; litterfall; and forest floor depth and biomass. Nineteen plots in north-central Virginia and western Maryland on which trees suffered heavy, moderate, or no defoliation were monitored over a two-year period. / Master of Science
190

Design and development of an instructional unit on integrated pest management (IPM): using the gypsy moth (Lymantria dispar (L.)) problem to teach IPM

Carroll, Belinda Stone 07 October 2005 (has links)
An instructional guide for high school science and agricultural education courses was designed around the topic of integrated pest management (IPM) and the gypsy moth (Lymantria dispar [L.]) problem in Virginia. Construction of the guide followed three phases—design, development, and evaluation—of the Instructional Development Institute (IDI) model of instructional design. Lessons were developed using information from Virginia agricultural education course competencies, national science standards, a conceptual model of IPM, and gypsy moth management references and contacts. A validation panel consisting of two educators and two gypsy moth managers provided a review of the guide. / Master of Science

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