Master of Science, The Ohio State University, 2011, Geological Sciences

Tropical glaciers can provide climatic information through changes in ice area through time and from ice core records contained within them. The glaciers near Puncak Jaya in Papua, Indonesia are the last remaining glaciers in the tropical West Pacific. Several satellite based studies have been conducted to assess the glacier recession through the area, but few intensive field and no ice cores studies have been conducted on these glaciers. A field expedition to Papua highland was conducted in May - June 2010 to drill ice cores from these glaciers and to collect rain samples from different elevation in the vicinity. Three ice cores were drilled, two to bedrock measuring 32.13 m (D1) and 31.25 m (D1B) in length and the third measuring 26.19 m (D2) in length. The stable isotope records were reproducible between the longer cores with significant δ18O variability of 5 to 6‰. High aerosol events were identified between 20 and 29 meters depth and in the top eight meters. This suggests that there is no melting throughout the glacier. The dating of D1 core has not been completed yet. Low tritium concentration in D1 core and high tritium concentration recorded in precipitation at the northern sites of Papua suggests that the glaciers may have melted below the 1950s/1960s bomb horizons. Eighty three rain samples were collected from different altitudes in the southern part of Papua. The analysis results suggest that the altitude effect dominates in the Papua region. The isotopic lapse rate is about 0.23‰/100 m and 1.80‰/100 m for δ18O and δD, respectively, greater than the continentality effect of 0.09‰/km. The isotopic compositions of the rain samples generally fall on the global meteoric water line. The meteorological data analysis from automated weather stations arrayed extending from the southern coastal region up to near the glaciers shows that the surface lapse rate is about 5°C/km. Greater diurnal temperature differences are identified at below 2,500 m a.s.l and at abo (open full item for complete abstract)

Committee: Lonnie Thompson PhD (Advisor); William Lyons PhD (Committee Member); Matthew Saltzman PhD (Committee Member) Subjects: Climate Change; Geochemistry; Geography; Geological; Geology

Doctor of Philosophy, The Ohio State University, 2006, Atmospheric Sciences

The upper ocean significantly influences tropical cyclone structure and intensity. These effects, however, are not well understood mostly due to a lack of oceanic and atmospheric boundary layer observations within the inner-core region. This study relates ocean-atmosphere energy exchange processes to mid-to-upper tropospheric latent heating using mesoscale inner-core convective burst events. A global survey of convective burst events in tropical cyclones from the year 1999 – 2001 was constructed. This study shows that 80% of tropical cyclones have at least one convective burst event and that convective burst events usually occur during the intensification phase of the storm life cycle. Latent and sensible heat flux estimates and a measure of upper-ocean energy utilization were calculated for the inner-core (<.5° radius) and the near-core (.5° - 1° radius). This study found that tropical cyclones generally utilize only about 8% of the total enthalpy flux available from the ocean/atmosphere boundary layer. Storms with convective bursts utilize more energy from the ocean (11%) than storms with no convective burst (2%). Sea-air fluxes are greatly enhanced (doubled) during convective burst time periods. These along-track ocean-atmosphere analyses was compared to vertical profiles of atmospheric latent heating calculated using a combined active and passive TRMM PR and TMI retrieval algorithm. Results show strong positive space and time correlations between ocean-air fluxes and mid-upper tropospheric latent heating. Additionally, the 30 storms analyzed were categorized by the presence or absence of convective burst events during the storm lifecycle. Composite atmospheric latent heating profiles constructed for each group show a two-fold release in energy for the storms with convective burst events compared to storms with no convective burst event. Finally, seven case studies are presented which attempt to resolve the upscale energy cascade of the tropical cyclone with a co (open full item for complete abstract)

Committee: Jay Hobgood (Advisor) Subjects:

Doctor of Philosophy, The Ohio State University, 2003, Atmospheric Sciences

Current numerical weather prediction models experience great difficulty in forecasting tropical cyclogenesis, primarily because of limitations of cloud parameterizations and observations. Forecasters have also struggled with the problem since they rely on the numerical models as an objective source of information. This research was performed with the aim of filling the void of objective guidance for tropical cyclogenesis. A new dataset of cloud clusters is created through the examination of infrared (IR) satellite imagery over the tropical Atlantic during the 1998-2001 hurricane seasons. Eight large-scale predictors of tropical cyclogenesis were then calculated from NCEP-NCAR Reanalysis dataset for each 6-hour interval of the cloud cluster life cycle extending back to 48 hours prior to genesis. Independent classifications were then performed on the entire dataset using both discriminant analysis (DA) and an artificial neural network (NN). The classifiers are fundamentally different from each other in that DA performs classifications based solely on linear trends in the predictors; the NN is potentially a more powerful classifier as it can find non-linear relationships in the data. The performance of each classifier was investigated through statistical scores and a series of case studies from the 1998-2001 Atlantic hurricane seasons. Tropical cyclogenesis is a rare event. Climatologically only about 15% of all cloud clusters develop into tropical depressions over the Atlantic Basin. The new cloud cluster database reflects that. 432 cloud clusters, of which 62 developed into tropical depressions, were tracked during the four seasons. Independent DA classifications show forecast skill over climatology. For the “prime” development season of August – October, the DA correctly forecast a higher percentage of clusters than climatology for all forecast periods. The most important predictors are latitude and the vertical shear structure. A comparison of DA forecasts with NN (open full item for complete abstract)

Committee: Jay Hobgood (Advisor) Subjects:

Master of Science, The Ohio State University, 2024, Civil Engineering

Many different parametric wind models have been constructed with the intent of providing accurate tropical cyclone wind fields for engineering applications. No matter which model is chosen, typical storm characteristics (e.g., intensity and size) are utilized to first generate the gradient-level (> 300-m) winds. From there, surface-level winds are calculated by applying a so-called wind reduction factor (WRF). While this type of approach is routinely used in parametric modeling, most of these models have a predetermined value for the WRF. This leads to the motivation to generate an adaptable WRF function based on the storm's characteristics. Using the surface-level (10-m) wind speed data retrieved from NASA's Cyclone Global Navigation Satellite System (CYGNSS) mission, fifty-four storms, between the years of 2018 and 2023, were compared to the aforementioned gradient winds. The CYGNSS data points were imposed on the generated gradient winds and a root mean square error calculation was run to yield the WRF corresponding with the smallest error. Through this analysis, two general trends were observed regarding WRFs: 1) a static, yet lower (compared to what is typically used) value of the WRF and 2) a dynamic, wind-dependent reduction factor both produced results that provided a better match to the CYGNSS data than the "baseline" WRF value used in the Advanced Circulation (ADCIRC) storm surge model. Using ADCIRC, the three different WRFs (baseline, static, dynamic) were tested on 5 storms between the years of 2018 and 2021. A statistical analysis of each simulation result was compared to the United States Geological Survey (USGS) peak stage elevations. Overall, the results show the CYGNSS-derived dynamic WRF increased the accuracy of storm surge when compared to the preexisting baseline value. The CYGNSS-derived dynamic WRF also led to slight overprediction in storm surge while the baseline and CYGNSS-derived static WRFs yielded underestimates, leading to the conclusio (open full item for complete abstract)

Committee: Ethan Kubatko (Advisor); Gil Bohrer (Committee Member); Joel Johnson (Committee Member) Subjects: Civil Engineering; Environmental Engineering

Doctor of Philosophy, The Ohio State University, 2024, Pharmaceutical Sciences

Cancers and leishmaniasis are distinct diseases, but the effects of each on people and communities are similarly devastating. Cancers cause over 10 million deaths worldwide each year, and are so widespread that nearly every person has lost a loved one to them, myself included. Leishmaniasis primarily affects tropical countries and in many places where access to medical care is limited, and the visceral form of the disease requires medical treatment to increase chances of survival above 5%. Both cancers and visceral leishmaniasis are diseases that the human immune system alone often cannot overcome, so the continued research into treatments is crucial to develop new and better tools to fight against these diseases. This dissertation details drug discovery efforts for two different projects, one against each disease; chapter 1 introduces readers to each disease state, chapter 2 describes the synthesis and biological evaluation of anticancer compounds, and chapter 3 describes the synthesis and biological evaluation of antileishmanial compounds. Following the serendipitous discovery of an antileukemia hit compound with an arylimidamide-azole scaffold, a series of analogs was synthesized to evaluate modifications to the scaffold. A robust structure-activity relationship (SAR) was developed through the synthesis of these compounds, and analysis of this relationship pointed to specific chemical modifications to the scaffold which improved their anticancer potency. Combining these favorable modifications led to compounds with >4-fold improved potency compared to the parent compound. Among the most potent compounds in this iv series was 2.9k, which displayed an IC50 value of 100 nM against the acute myeloid leukemia (AML) cell line OCI-AML3. Promising compounds in this series were then further evaluated for broad anticancer activity, pharmacokinetic properties, and mechanism of action as described in chapter 2. The antileishmanial compounds described in this dissertation (open full item for complete abstract)

Committee: Karl Werbovetz (Advisor); Xiaolin Cheng (Committee Member); James Fuchs (Committee Member) Subjects: Biology; Chemistry; Organic Chemistry; Pharmaceuticals; Pharmacology; Pharmacy Sciences

PhD, University of Cincinnati, 2022, Arts and Sciences: Biological Sciences

In this research, we focused on the modern forest as a baseline to estimate the forest resources that the ancient city of Yaxnohcah had for its development. Maya archaeology experienced a sudden change with the acquisition of light detection and ranging (lidar) data. It became especially important in dense tropical forested areas covering the archaeological sites. The lidar beam penetrates the canopy revealing the ground surface and any indica¬tion of human modification of the terrain. In addition, lidar also creates a point cloud that recreates the structure of the forest in three dimensions. However, the lidar data does not provide a reference for species identification of the vegetation measured. Because of this, field surveys are required to obtain information on vegetation composition and tree species measurements. Yaxnohcah is located inside the Calakmul Biosphere Reserve in a mostly undisturbed forest in the south of the state of Campeche, Mexico. The first step was to identify the vegetation communities that composed the landscape. With forest surveys and a supervised satellite image classification, we defined the forest as upland, transition, lowland (bajo), and wetland. We carried out stratified surveys of the vegetation in transects, where tree measurements and species were recorded. Biomass was then quan¬tified as an approach to forest resources available, obtaining 240 Mg ha-1 for upland, 196 Mg ha-1 for tran¬sition, and 80 Mg ha-1 for bajo. Identifications of archaeobotanical samples provided the link between the modern situation and the Maya period regarding the vegetation composition. Botanical remains from ar¬chaeological pits and reservoirs, including pollen, charcoal, and eDNA, intersected with species in the modern forest providing information on the continuity of the forest. However, few species that appear in the archaeological record are not recorded in the present vegetation. In addition, pollen sequences pro¬vided a temporal reference of veg (open full item for complete abstract)

Committee: David Lentz Ph.D. (Committee Member); Robert Bye Ph.D (Committee Member); Eric Tepe (Committee Member); Nicholas Dunning Ph.D. (Committee Member); Theresa Culley Ph.D. (Committee Member) Subjects: Archaeology

Doctor of Philosophy, The Ohio State University, 2022, Geography

Bofedales are ecologically defined as an Andean mountain wetland and peatland system, which constitute one of the most highly biodiverse and important hydroecological systems of the high Andes. Their geographic distribution is scattered across high mountain plateaus and glacier valleys across the Andean Cordilleras. Bofedales provide key environmental, social, and cultural services for pastoralist communities, including critical habitat for a wide range of wild flora and fauna, including also livestock animals and endemic birds. Alterations to the regional climate processes, land use change, and rapid glacier retreat are affecting the sustainability and equilibrium of bofedales, leading to their degradation. Despite their importance for ecosystem services, there is a substantial gap in the geographical distribution of bofedales, which is a critical need in order to understand current threats and vulnerabilities to these systems, and a dearth of information about the range of biophysical patterns regarding the classes of bofedales and differing bio-geographical characteristics of bofedales across the Andean region, including the seasonal to interannual patterns of vegetation productivity. In this research, I developed and applied new methodologies utilizing state-of-the-knowledge Earth Observation Systems analysis with extensive ground-truthing, archival research of published studies, and mixed botanical field methods to create an Atlas of bofedales in the Southern Tropical Andes, including the countries of Peru, Bolivia, Chile and Argentina. In particular, this research has resulted in the development of mapping products to address the academic gaps in bofedal distribution including 1) A baseline inventory of varying bofedal classes and a regional map of their distribution and size of bofedales for the Southern Tropical Andes, and 2) A comparative geo-botanical analysis of bofedal classes in three regions of the Bolivian Altiplano, and 3) An examination of the annu (open full item for complete abstract)

Committee: Bryan Mark (Advisor) Subjects: Geographic Information Science; Geography; Physical Geography; Remote Sensing

Doctor of Philosophy (PhD), Wright State University, 2022, Environmental Sciences PhD

Mercury (Hg) is a neurotoxin that can have detrimental impacts on the human nervous system and on brain development in infants. Methylmercury (MeHg) is the most toxic form of Hg and can concentrate to potentially harmful levels in higher levels of marine food webs. Production of MeHg in oxic water columns is poorly understood due to lack of knowledge of the mechanisms of formation and distribution. Recent work has reported widespread, putative Hg methylation genes in nitrite oxidizers, but any relationship with nitrifiers is unknown. This work focuses on Hg water column distribution, speciation, and methylation. The aims of this dissertation are to quantify: (1) rates and distribution of HgT and MeHg in the western basin of Lake Erie; (2) Hg methylation and nitrification rates in the Tropical North Atlantic Ocean; and (3) Hg species distribution in the Central Pacific Ocean. In Lake Erie, a Laurentian Great Lake, the mean fraction of total Hg as MeHg in water column measurements from lake areas near three Lake Erie river inputs (summers of 2018, 2019, and 2021) were comparable (~5%), suggesting similar biogeochemical cycling for rivers feeding Lake Erie. Estimated river fluxes of MeHg were an order of magnitude greater than in situ production, and greater from the Detroit River (9.5 kg yr–1) than from either the Maumee River (0.78 kg yr–1) or Sandusky iii Bay (0.03 kg yr–1), as expected since the Detroit River accounts for about 95% of total water discharge into Lake Erie. These results suggest that the Detroit River is a major source of MeHg from the upper Great Lakes basin to western Lake Erie. Overall, Hg concentrations and fluxes observed in this study were up to orders of magnitude less than those reported in previous decades, which may be a positive result of the Ohio Clean Air and Water Act of 2004. In a marine system, potential Hg methylation and nitrification rates were measured in Western Tropical North Atlantic Ocean surface waters (June and July 2019 (open full item for complete abstract)

Committee: Silvia Newell Ph.D. (Advisor); Mark J. McCarthy Ph.D. (Committee Member); Sarah Tebbens Ph.D. (Committee Member); Alison Agather Ph.D. (Committee Member); Carl Lamborg Ph.D. (Other) Subjects: Environmental Science

Doctor of Philosophy, The Ohio State University, 2022, Geography

This dissertation comprises of a multi-part investigation into the impacts and contributions of debris-covered glaciers to the surface hydrology of the Cordillera Blanca, Peru. Due to the circumstances surrounding the global pandemic, the originally planned in situ dataset was not collected; however, following a pivot in research goals and objectives, field collected (prior to 2020) streamflow and water quality data, and remotely sensed imagery were used to answer the slightly broadened questions of this dissertation. First, without a specific focus on debris-covered glacier catchments, long-term hydrological shifts were identified throughout the past 70-years, and short-term daily fluctuations were assessed throughout the Rio Santa watershed. Multiple change points were identified to have occurred over the historical record, with the most recent changes in the 2000s that indicate lower rates of loss in discharge now compared to prior decades. High-temporal resolution discharge data is presented which provides evidence that diurnal changes in streamflow are driven by seasonal fluctuations and have not undergone significant shifts in timing or amplitude during the past 14-years. Second, high-resolution satellite imagery was used to calculate the spatial and temporal changes and estimate volumes of supraglacial ponds on the surface of debris-covered glaciers for the first time across the Peruvian Andes. Expanding the study area beyond the Cordillera Blanca allowed for the opportunity to test patterns in debris-covered glacier ponds more broadly and place the Cordillera Blanca in a regional context. From these analyses, debris-covered glacier pond area maxima were recorded to have occurred in 2012 and 2013 across the Peruvian Andes. Furthermore, as minimum temperatures significantly rose over the past 11 years, a decrease in total supraglacial pond area was measured. Finally, water volume estimates provide strong indications that debris-covered glaciers contribute sign (open full item for complete abstract)

Committee: Bryan Mark (Advisor); Michael Durand (Committee Member); Robert Hellstrӧm (Committee Member); Alvaro Montenegro (Committee Member) Subjects: Environmental Science; Hydrology; Physical Geography; Water Resource Management

Master of Arts, The Ohio State University, 2022, Geography

Improving tropical glacier modeling capacity is crucial for deriving climatological insight from tropical glacier fluctuations on historical to multi-millennial timescales and for predicting socially relevant glacier environmental changes under anthropogenic climate warming. Using the glacierized Queshque Valley of Peru's Cordillera Blanca as a case study, this thesis first develops data assimilation and calibration methods to adapt a coupled temperature-index mass balance and glacier flow model to tropical settings. The calibrated model is applied to project glacier evolution in the valley under an ensemble of climate change scenarios, confirming the high probability of near complete deglaciation by the end of this century. Despite the glacier's current trajectory, moraine features signal that ice once extended about 6km further down valley. Three cosmogenic nuclide dated moraines reveal extended ice cover at 10.8ka, 9.4ka, and 6.2ka BP, and historical maps show that the glaciers have retreated considerably since 1962 CE. Equilibrium experiments are used to identify all possible climatic conditions producing stable glaciers at the positions marked by the moraines and historical ice limit. Relative to the 1985-2015 CE climatic baseline, results suggest that valley temperatures were 2.9-1.9˚C cooler at 10.8ka BP and at least 1.0˚C cooler at 9.4ka BP. Proximity between the 9.6ka and 6.2ka moraines makes their climatic signatures difficult to distinguish. Finally, the equilibrium experiment confirms that in 1962 the glacier was already far out of balance. In summary, this thesis presents a data-intensive approach to improving model performance on a tropical glacier, enabling accurate ice loss projections, and helping to constrain paleoclimatic interpretations of tropical glacier geomorphology.

Committee: Bryan Mark (Advisor); Zhengyu Liu (Committee Member); Ellen Mosley-Thompson (Committee Member) Subjects: Geography; Geomorphology

Honors Theses, Ohio Dominican University, 2021, Honors Theses

Leishmaniasis is a neglected tropical disease which affects millions of people every year across 6 continents. Current antileishmanial drugs have become less effective due to resistance, have a high toxicity, and are too expensive for many lower socioeconomic countries. New drug candidates can be explored and synthesized by natural drug synthesis and high throughput screening (HTS). This paper aimed to explore both methods in search of novel antileishmanial compounds. For the natural product approach, the ABC ring of berberine will be optimized to improve its antileishmanial properties. For the HTS approach, a piperazine based small molecule has been synthesized and will be evaluated for its antileishmanial properties.

Committee: Janet Antwi (Advisor); Blake Mathys (Other); Arlene Ramkissoon (Committee Member); John Marazita (Committee Chair) Subjects: Biochemistry; Biology; Biomedical Research; Chemistry; Epidemiology; Organic Chemistry; Parasitology; Pharmaceuticals; Pharmacology

Doctor of Philosophy (PhD), Ohio University, 0, Instructional Technology (Education)

At a time when the world is facing a range of significant challenges, including a rise in air temperature, rapidly evolving droughts in some areas, and floods, new technology in education can help inform people of current issues that may not be close to them but, nevertheless, can have a significant impact in the future. Our planet has been warming steadily for over a century, and the preponderance of evidence has pointed at human action as the main contributor to the change (Hansen et al., 2010). The evolution of technology has brought tremendous change. Virtual Reality (VR), 360-degree video, has the potential to bring the environment to the students since it can provide a close to a real-life situation. The use of VR for educational purposes has been quite unknown to most school systems. There are many gaps that need to be investigated prior to the effective implementation of VR-learning, such as the factors that influence students' intention to use it. This study fulfilled some of these gaps by focusing on the potential of using VR for future education and raising awareness of the climate change occurring in remote areas, specifically tropical regions. The findings of this study will hopefully encourage students to play a more responsible role in the development and implementation of VR education worldwide and help enhance the academic quality of courses for instructors and students. This study examined students' behavioral intentions towards using VR in their learning about climate change utilizing the Technology Acceptance Model of Davis (1989), combined with the spatial presence experience scale (Hartmann et al., 2015). Phase 1 was created in order to understand students' salient beliefs about the use of VR for educational purposes and learning about climate change. Furthermore, 65 students participated in this phase and reported that VR can be beneficial for educational purposes to learn about global climate change, and 95.2% of participants fully agreed. Ph (open full item for complete abstract)

Committee: Greg Kessler (Advisor); Gordon Brooks (Advisor) Subjects: Climate Change; Educational Technology; Environmental Education

MA, Kent State University, 2020, College of Arts and Sciences / Department of Geography

Rainfall components likely differ in the magnitude and direction of their long-term changes for any given location, and some rainfall components may carry a greater regional signal of rainfall change than rainfall totals. This study, therefore, sought to evaluate the magnitude of change of each rainfall component relative to other components, and the greatest locations or regions of change across all the rainfall components in West Africa. Hourly rainfall data from the ERA5 reanalysis dataset was used to derive twelve rainfall components, which were evaluated for long-term means, interannual variability and long-term changes. The spatio-temporal magnitude of changes among the components was estimated using absolute z-score values of the slopes of each component and the count of significant grid-point trends. Teleconnections with ENSO were also assessed for each rainfall component and each region (within each rainfall component). Rainfall components were mostly similar in the spatial patterns of long-term means and interannual variability, but considerable differences exist in the spatial pattern of long-term trends. For rainfall totals and heavy rainfall frequency, the central Sahel is witnessing increasing trends while the western Sahel is experiencing significant decreasing trends, and this dichotomy has been widely reported in the literature. In general, decreasing trends predominate in the study area, especially in the northwestern Congo Basin, where annual rainfall is decreasing by 120mm per decade. Rainfall frequency accounts for 62% of all significant grid-point trends for the whole domain. In contrast, rainfall totals account for 27% of all combined significant trends across the domain, while rainfall intensity (4.6%), rainfall timing (5.2%), and rainfall seasonality (1.2%) account for the remaining signals of change. Most of the changes among the rainfall components are in the Tropical Wet and Dry regions (59% of all significant trends); the Saharan and Equ (open full item for complete abstract)

Committee: Cameron Lee PhD (Advisor); Scott Sheridan PhD (Committee Member); Tom Schmidlin PhD (Committee Member) Subjects: Climate Change; Geography

Doctor of Philosophy, The Ohio State University, 2020, Civil Engineering

Storms often severely impact coastal areas, posing risks to life, infrastructure and the economy. In major coastal centers of population and commerce, extensive flood protection systems are implemented to mitigate storm impacts and reduce risks. If the flood barriers that comprise these systems fail, e.g., by erosion, excess capacity, or some design flaw, then extensive losses can be incurred to protected areas. Finite element models for solutions to the shallow water equations are frequently used to project risks to coastal areas due to impacts of storm surge; however, despite the significant risks posed by flood barrier failures, the models in use typically are limited in regard to modeling these risks, only considering one of the many different modes in which these systems may potentially fail, overtopping. Additionally, the finite element models exert considerable computational demand, often constraining their applications to high performance parallel computing environments. In this study, we seek to enhance the flood barrier modeling capabilities of current finite element modeling frameworks designed for projecting risks due to storm surge, by seeking cost effective solutions that minimize additional computational demands as well as by optimizing the currently existing techniques. Discussion of these developments primarily is in the context of a discontinuous Galerkin (DG) based framework for modeling of shallow water flow. We demonstrate improvements on the efficiency of this approach by implementing DG-optimized strong stability-persevering Runge--Kutta (RK) time stepping, which optimizes for the stability region of the RK method, and can reduce the computational demand by at least 5% for low-order approximations. Additional consideration is owed to quadrilateral based finite element meshes, which can nearly half the computational demand exerted by more commonly used triangular meshes. Finally, we demonstrate fast and effective approximations of storm surge b (open full item for complete abstract)

Committee: Ethan Kubatko Dr (Advisor); Abdollah Shafieezadeh Dr (Committee Member); Gil Bohrer Dr (Committee Member) Subjects: Civil Engineering; Environmental Engineering; Fluid Dynamics; Geotechnology; Meteorology; Ocean Engineering

Doctor of Philosophy, The Ohio State University, 2019, Comparative and Veterinary Medicine

Extensive research of foot-and-mouth disease virus (FMDV) has been conducted concerning basic etiology of the related disease and transmission potential from livestock and livestock products; (Argentine-United States Joint Commission on Foot and Mouth Disease, 1966) with a subset of research determining optimal conditions for environmental survival of the virus.(Bachrach, Breese, Jr., Callis, W.R., & Patty, 1957; Cottral, 1969; Dimopoullos, 1960; Pirtle & Beran, 1991) However, this subset was conducted in the early to mid-20th century in Northern Europe and the United States which is not easily generalized to today's endemic locations of Southern Asia and Africa.(OIE, 2017; Spickler, 2015) To understand the impacts of these data a Cox Proportional Hazard analysis model was developed to evaluate FMDV survival parameters across these studies. Preliminary analysis suggests that environmental matrices and relative humidity decrease the hazard of viral inactivation while temperature increases this hazard. Additionally, questions remain about spatial and temporal patterns of environmental persistence of FMDV in outbreak locations like Cameroon, West Africa, where both sedentary and mobile cattle populations exist. Environmental samples including soil, fomite, and air from FMD outbreaks were analyzed with rRT-PCR to detect FMDV RNA from three herds in Ngaoundere, Cameroon at designated locations from clinically infected cattle. These data were used to determine spatial and temporal transmission patterns and the theoretical implications of environmental persistence of FMDV in tropical climates. Theoretical implications were evaluated with an agent-based model (ABM) that included data on movement of mobile cattle herds from the Far North, Cameroon. FMD results in animal mortality and morbidity, imparts trade restrictions on developing economies, and burdens veterinary infrastructure with expensive control programs. These consequences greatly impact regional economies and fo (open full item for complete abstract)

Committee: Rebecca Garabed (Advisor); Michael Bisesi (Committee Member); Andrew Bowman (Committee Member); Stephen Matthews (Committee Member) Subjects: Agriculture; Animal Diseases; Biostatistics; Ecology; Environmental Science; Epidemiology; Public Health

MS, University of Cincinnati, 2019, Arts and Sciences: Geology

Land snails are among the most abundant terrestrial invertebrates preserved in the Quaternary continental sedimentary record, ranging geographically from the Tropics to the high Arctic tundra. The oxygen (d18O) isotopic composition of these shells have the potential to provide invaluable paleoenvironmental information across space and time. However, reliable paleoenvironmental inferences from fossil and sub-fossil shells require a detailed modern calibration and validation assessment if the taxa and locality have not been investigated for this purpose before. The bulk of published calibration studies has focused on the middle latitudes of the northern hemisphere whereas tropical latitudes have received minimal attention. This thesis investigates the lowest latitude record of modern land snails from the northern hemisphere and sets the foundation for future paleoenvironmental research in the Tropics using land snails. Four small (<10 mm) species of modern land snails from Trinidad Island (latitude: 10.6918° N, longitude: 61.2225° W) were collected along an east-to-west environmental gradient, isotopically analyzed, and compared to instrument and modeled climate data. Results indicate that while three species overlapped in d18O values, Succinea specimens were consistently higher in d18O. Thus, mixing of snail species in Trinidad may complicate paleoenvironmental inferences. No significant isotopic variations were documented between coastal and inland sites, suggesting similar precipitation d18O values along the transect. The d18O values of snails from Trinidad primarily track the local rain d18O values with a high degree of accuracy, and therefore, ancient shells of these species may be used as proxies for rain d18O throughout the Quaternary in Trinidad and other nearby Caribbean islands. The integration of new d18O values from Trinidad shells presented here with published data of snails across North America reinforces previous observations that land snails mimic vari (open full item for complete abstract)

Committee: Yurena Yanes Ph.D. (Committee Chair); Carlton Brett Ph.D. (Committee Member); Amy Townsend-Small Ph.D. (Committee Member) Subjects: Geology

Master of Arts, The Ohio State University, 2019, Geography

The goal of this research is to develop a new proxy record sensitive to water availability in the tropical Andes, where climate change threatens glacial reserves of water stored as ice. As such, this study constitutes the first investigation into the radial growth of the newly described tropical tree species, Polylepis Rodolfo-vasquezii. In the dry season of 2017, a sample set of cores were extracted from a P. rodolfo-vasquezii montane forest in the Cordillera Huaytapallana in the central Peruvian Andes. Standard dendrochronological techniques were applied to the samples to produce a 77 year-long annually resolved chronology, from 1940 to 2016. Correlation analysis between tree ring widths and station data as well as regional anomalies and reveal that P. rodolfo-vasquezii is sensitive to wet season precipitation and discharge from the nearby Shullcas River. The strongest relationship with the tree rings was late wet season discharge. Based on these correlations, the first-ever monthly and seasonal discharge reconstructions were produced for the Shullcas River. The calibration-verification statistics for each model indicate that there are varying degrees of predictive skill in the reconstructions produced. The optimal reconstruction was for the average of April-May discharge. This work provides evidence that Polylepis rodolfo-vasquezii is a useful species for dendrochronological research and highlights its relationship to moisture in the Cordillera Huaytapallana.

Committee: Bryan Mark PhD (Advisor); Alvaro Montenegro PhD (Committee Member); Ellen Mosley-Thompson PhD (Committee Member) Subjects: Environmental Science; Geography; Hydrologic Sciences; Paleoclimate Science

Ph.D., Antioch University, 2018, Antioch New England: Environmental Studies

Changes in forest cover especially changes within tropical forests, affect global climate change, together with ecosystems and forest carbon. Forests play a key role in both carbon emission and carbon sequestration. Efforts to reduce emissions through reduced deforestation and degradation of forests have become a common discussion among scientists and politicians under the auspices of the United Nations Programme on Reducing Emissions from Deforestation and Forest Degradation (UN-REDD Programme). This dissertation research assessed the impacts of land use land cover change upon ecosystem services from a protected area focusing on forest carbon distribution and vegetation mapping using remote sensing and geographical information systems (GIS). I also assessed Rwanda's preparedness in the United Nations global program, Reducing Emissions from Deforestation and forest Degradation, Measuring, Monitoring, Reporting, and Verifying (REDD+MMRV). I carried out research in Nyungwe National Park (NNP), one of four National Parks of Rwanda. NNP is a montane tropical forest located in the Albertine Rift, one of the most biodiverse places in central and east Africa. I used remote sensing and field data collection from December 2011 and July 2012 in the western part of the Park to assess distribution and quantities of aboveground (ABG) forest carbon using generalized allometric functions. Using Landsat data together with 2009 high resolution color orthophotos and groundtruthing, I analyzed land cover changes between 1986 and 2011 for NNP. The land-use land cover change analysis showed that between 1986 and 1995 there was a minor increase in forest cover from 53% to 58% while from 1995-2003 a substantial decrease in forest cover occurred. Between 2003 and 2011 was a period of recovery with forest cover increasing by 59%. Vegetation analysis based on a 2009 Park biodiversity survey yielded 13 vegetation communities based on dominant and co-dominant species. Macaranga kilimandschar (open full item for complete abstract)

Committee: Beth Kaplin PhD (Committee Chair); Peter Palmiotto DF (Committee Member); Naikoa Aguilar-Amuchastegui PhD (Committee Member) Subjects: Environmental Studies; Geographic Information Science; Remote Sensing

Bachelor of Sciences, Ohio University, 2018, Geography

Over recent decades, a rapidly growing body of literature has become dedicated to discovering and expanding knowledge related to Antarctic climate change. The vast majority of these studies have involved discussions over the rising temperature trends over large portions of the continent, especially over the West Antarctica and the Antarctic Peninsula, while also investigating the reason behind the lack of significant warming in East Antarctica. More recently, there has been an increase of studies related to the deepening of a semi-permanent low pressure center called the Amundsen Sea Low (ASL), which is responsible for a large percentage of the atmospheric circulation around the Antarctic Peninsula. With direct observations on the continent very limited in space and time before ~1957, more intensive, long-term studies have thus far proved difficult. Antarctic pressure reconstructions, as well as the Community Atmospheric Model, Version 5 (CAM5), are analyzed throughout this thesis to further our understanding of how tropical sea surface temperature changes over the 20th century affect atmospheric circulation and pressure variability on and near the Antarctic continent. These datasets indicated that tropical SSTs are partially responsible for the intensification of the Amundsen Sea Low, as well as more widespread negative pressure trends over the entire continent. Antarctic pressure trends and variability due to tropical SSTs were also closely linked to large scale atmospheric circulation variability associated with climate modes, including the SAM, ENSO, and the IPO. The reliability of this model was tested using reanalysis data as well as statistically accurate reconstruction data, which are representative of a real-world scenario. The tests not only revealed the CAM5 data used here was reliable, but also that the similar behavior of these datasets stresses the important role tropical SSTs play in Antarctic climate change, even perhaps more than previously reali (open full item for complete abstract)

Committee: Ryan Fogt Dr. (Advisor) Subjects: Atmospheric Sciences; Climate Change

Master of Science, The Ohio State University, 2018, Earth Sciences

While there are only a handful of locations around the world today where tropical glaciers still exist, and given their high sensitivity to climate change they can be used as indicators of change and for interpretations of the mechanisms driving climate change. Recent technological advances now provide an opportunity to modify the way glaciers are observed and measured. These are applied to the Qori Kalis glacier in Peru and the ice fields on Kilimanjaro in this work. New developments have opened doors for digital photogrammetry software such as the Leica photogrammetry suite and stereo analyst from ERDAS, which offer stereoscopic tools with the ability to plot the ice extent in a three dimensional image. The resulting three-dimensional digital content offers more flexibility in analysis, quantification, visualization, and improves the documentation of retreating glaciers. It is possible to produce both two-and three-dimensional area estimations and volume loss for glaciers such as Qori Kalis, the main outlet glacier of the Quelccaya ice cap (Peru), and the Kilimanjaro ice fields, Tanzania. Satellite imagery was purchased for 2017 and used to acquire a more accurate measure of the ice loss than provided by the terrestrial or aerial imagery that was used previously. This new approach simplifies the measurement and calculation process and when measurements made using the digital method are compared with those from the earlier measurements they are found to be comparable. The retreat of Qori Kalis is analyzed from 2004 to 2017 while the Kilimanjaro ice fields are analyzed from 2010 to 2017 and the resulting data are compared to past measurements from various studies. Both tropical locations show a decrease in the ice cover along a linear regression from 2004 until 2017. There is evidence for both a retreat of the ice and a thinning of the surface at both sites. Kilimanjaro's ice fields continue to separate into multiple smaller bodies and are losing ice fro (open full item for complete abstract)

Committee: Lonnie Thompson Dr. (Advisor); Ellen Mosley-Thompson Dr. (Committee Member); Rongjun Qin Dr. (Committee Member) Subjects: Civil Engineering; Climate Change; Earth; Environmental Geology; Geographic Information Science; Geology