After a Radiological Dispersal Device (RDD) event, there will not be time to transport people to a whole-body-counter (WBC), since it is a specialized instrument. This work will assess the feasibility of using handheld spectrometers for measuring the radioactivity that may have been inhaled by a victim as a consequence of an RDD event. Measurements were made with a handheld isotope identifier using a slab phantom and several radioactive point sources. A Lawrence Livermore National Laboratory (LLNL) Realistic Torso Phantom and a set of phantoms based on Medical Internal Radiation Dose (MIRD) reports were also used in this work. These phantoms include the human skeleton and have tissue-equivalent organs. Computational models were developed of all of the phantoms using the Monte Carlo Transport code MCNP. After validation of the computer model, MCNP runs were conducted using other sources that are likely to be used in a RDD. Calculations were then done to find the Minimum Detectable Activity (MDA) of all sources used. The Minimum Detectable Dose (MDD) was then calculated for the MIRD phantoms at various times after inhalation.

A Radiological Dispersal Device (RDD) is any device that releases radioactive material into the environment (e.g. Dirty Bomb). Depending on the size of the explosion, location, and the weather conditions the affected area could be several city blocks. In such an event there could be hundreds, even thousands of contaminated victims seeking medical treatment. One concern in the healthcare industry is the uncertainty of the level of radiation exposure to the healthcare providers from these contaminated patients. The intention of this study is to estimate the levels of skin contamination for victims arriving at the hospital needing conventional medical treatment. Given a skin contamination of the victim the effective dose rate to the healthcare providers can be estimated in certain scenarios. The effective dose rate will determine how long the healthcare provider would be able to care for the victims.

The encrusting sponge Terpios hoshinota is a cyanobacteriosponge with symbiotic photosynthetic cyanobacteria. It covers live corals causing their death. Corals at Green Island were suspected to be infected by Terpios hoshinota in 2006, and field investigations indicated there was massive propagation of the species in both Green Island (Lyudao) and Orchid Island (Lanyu) in 2008 to 2010. We propose two hypotheses, either by Self-Seeding or by Long-Range Dispersal, that explain the fast propagation of Terpios hoshinota in the islands offshore of southeastern of Taiwan. We use ribosomal DNA and mitochondria DNA as molecular markers to investigate how the sponge disperses locally and in a greater geographic scale. A total of 110 samples, from Taiwan: Green Island, Orchid Island, and Kenting (Wanlitong). Japan: Okinawa, Nakijin, Miyako, Bise, Shiraho, Arahama Kumeshima, Yakomo (Okinoerabu), San (Takunoshima), and Xisha Island of China, were collected. Internal Transcribed Spacer 2 (ITS2) from ribosomal DNA and cytochrome oxidase I (COI) from mitochondria DNA are used as markers to infer population structure of Terpios hoshinota. No genetic variation within COI sequence over all sponges from Taiwan to Japan and China was found, although the only sponge sample from Wanlitong in Kenting had three variable sites, which suggest different species of Terpios hoshinota. Based on ITS2 analysis, haplotype diversity (h) is commonly high among most populations, but with different single haplotype found at Green Island and Arahama (Japan). Pairwise population differentiations (FST) are usually high and significant among populations supporting self-seeding, although Bise, Shiraho and Lanyu populations showed no significant differentiation that supports long-range dispersal. Analysis of Molecular Variance (AMOVA) shows no population subdivision; however, genetic differentiations among populations are significantly greater than within populations. TCS analysis indicates that single haplotype in Green Island is originated from Lanyu, and populations in Bise are widely dispersed over other sponge populations in Taiwan and Japan regions. By evidence of TCS analysis with nucleotide diversity, haplotype diversity and field investigation, Bise is the origin of Terpios hoshinota among populations within this study. Frequency of sequence haplotypes indicates one dominant haplotype is shared among most of the sponge populations, and the dominated sponge haplotype takes highest proportions of local populations. The existence of dominant haplotype may result from better dispersal or reproduction ability than other haplotype in populations. Nested clade analysis shows that populations mainly have restricted gene flow with some clade have contiguous range expansion. We suggest that populations of Terpios hoshinota propagate mainly by self-seeding method with occasional long-range dispersal event that leading to genetic connection among populations and obscuring evidence of isolation by distance in these populations. In Green Island, we consider local populations as undergoing explosion within past several years and propagate by self-seeding method coming from single lineage of Lanyu. Populations in Lanyu may come from Bise, Shiraho, and Yakomo, yet may still in status of population explosion. Populations in Japan may underwent founder effect with rapid population growth, while most populations are rarely interact with each other showing deep genetic differentiation among islands, and Bise is the origin of Terpios hoshinota in this study. Not all of the sponge individuals have ability to dominate local populations, expect for one special haplotype of Terpios hoshinota is capable of dominating local population in both range and quantity, which also has capability of spreading across islands as larger distances than its habitats range in Taiwan and Japan.

As radiation specialists, one of our primary objectives in the Navy is protecting people and the environment from the effects of ionizing and non-ionizing radiation. Focusing on radiological dispersal devices (RDD) will provide increased personnel protection as well as optimize emergency response assets for the general public. An attack involving an RDD has been of particular concern because it is intended to spread contamination over a wide area and cause massive panic within the general population. A rapid method of triage will be necessary to segregate the unexposed and slightly exposed from those needing immediate medical treatment. Because of the aerosol dispersal of the radioactive material, inhalation of the radioactive material may be the primary exposure route. The primary radionuclides likely to be used in a RDD attack are Co-60, Cs-137, Ir-192, Sr-90 and Am-241. Through the use of a MAX phantom along with a few Simulink MATLAB programs, a good anthropomorphic phantom was created for use in MCNPX simulations that would provide organ doses from internally deposited radionuclides. Ludlum model 44-9 and 44-2 detectors were used to verify the simulated dose from the MCNPX code. Based on the results, acute dose rate limits were developed for emergency response personnel that would assist in patient triage.

A fundamental question of long standing in the study of life on Earth is, “Why are there so many species?” This question concerns the distribution of and relationships among species in the present day, but also requires an understanding of the history of diversity. Patterns of diversity result from multiple, interconnected ecological processes operating at different spatial scales. The goal of this research is to gain knowledge about processes that control diversity by using fossil data to provide a temporal perspective that is unavailable when studying modern ecological communities. The fossil record provides the only natural historical account of changes in the diversity of ecological communities in Earth’s past. This research examines the taxonomic composition and diversity of brachiopod paleocommunities in the Delaware Basin of west Texas (Guadalupe Mountains National Park). The study interval is the Bell Canyon Formation, a 5.4-Myr interval of upper Middle Permian (Capitanian) siliciclastic and carbonate rocks deposited on the toe-ofslope of the basin. Silicified brachiopods extracted from the carbonate rocks provide the basis to test two hypotheses: (1) the taxonomic composition of local fossil brachiopod paleocommunities remains uniform, and (2) the changes in diversity of local fossil brachiopod paleocommunities reflects the relative importance of regional processes. Multivariate analyses of clustering analysis and ordination, diversity partitioning, and rank abundance plots are used to evaluate brachiopod taxonomic composition and diversity within an ecological framework. Sequence stratigraphic analysis provides the means to place the results within an environmental context related to sea-level changes. Results indicate that the reorganization of brachiopod paleocommunity structure coincides with major basinal-scale disruptions. Large disruptions allowed rare taxa and invaders from outside the basin to become dominant within paleocommunities. The dynamics within paleocommunities do not appear to prevent the replacement of the incumbent taxa with new taxa. The importance of these findings indicate that paleocommunities are not static through this interval and can be perturbed into configurations with new dominant taxa. Therefore, ecological responses of paleocommunities are resolvable at the geological time scale.

The kingdom Fungi is taxonomically and ecologically diverse, containing an estimated 1.5 million species. Fungi include decomposers, pathogens, and plant and animal mutualists. Many fungi are microorganisms, and the processes shaping microbial diversity may be fundamentally different from those that shape plants and animals. However, ecologists do not yet fully understand how fungal species are distributed over space and time. Using fungi that inhabit the water of Sarracenia carnivorous pitchers, I describe inter and intraspecific fungal diversity and investigate the processes that shape fungal diversity. I introduce these concepts in Chapter 1. In Chapter 2, I describe changes in fungal species diversity over space and time. I enumerated fungal species in five Sarracenia populations across the United States and Canada, and show that thousands, but not hundreds of kilometers separate distinct fungal communities. I also sampled a single Sarracenia population over a Sarracenia growing season, and found that young fungal communities are significantly different from older fungal communities. Observed patterns correlate with environmental factors including temperature and pitcher pH, and with the presence or population structure of pitcher inhabiting arthropods. In Chapter 3, I describe dispersal of and competition among three common pitcher fungi. I tracked Candida glaebosa, Rhodotorula glutinis, and Pseudozyma aphidis appearances in pitchers in a single Sarracenia population, and show that different appearances reflect different dispersal times. I also describe interactions between dispersal and competition in microcosms: high numbers of propagules introduced into a microcosm give a competitive advantage to investigated fungi. In Chapter 4, I describe changes in genotype composition of a population of Candida glaebosa, which is widespread and abundant in pitchers, and disperses early in the season. I observed three C. glaebosa populations in five locations; C. glaebosa population structure does not reflect broader community structure as described in Chapter 2. Population structure instead correlates with host taxonomy, and I contrast inter and intraspecific diversity patterns and the processes that potentially cause such patterns.

published_or_final_version / abstract / toc / Ecology and Biodiversity / Master / Master of Philosophy

No description available.

<p>Adaptation is central to our understanding of the origin of biological diversity. Yet whether adaptive divergence promotes the formation of new lineages remains poorly understood. My dissertation addresses the role of adaptive divergence in diversification and speciation. I also investigate an alternative mechanism: dispersal, which can promote diversification and speciation through its effects on gene flow and allopatry. To address the role of divergent adaptation and dispersal in the process of diversification, I take an integrated approach, combining both comparative methods with quantitative genetics to characterize patterns of diversification and speciation in the tribe Brassiceae and genus Cakile. I start with a comparative study of the role of dispersal and adaptation in diversification, and then focus on the role of climatic and latitudinal divergence in the processes of adaptive divergence and speciation. In general, I find limited evidence for the role of divergent adaptation in the evolution of intrinsic reproductive isolation. Diversification in the tribe Brassiceae appears to be mediated by dispersal ability, while in the genus Cakile, the evolution of intrinsic reproductive isolation is largely independent of ecological divergence. Thus, while divergent adaptation to novel habitats and climate are likely occurring in Brassiceae, mediated in part by the evolution of long-distance dispersal, the evolution of intrinsic genic reproductive barriers appears to not be influenced by adaptation.</p> / Dissertation

No description available.