This thesis is a study of the swimming locomotion of the polychaete worm, Nereis diversicolor. Previous research has shown that there are two distinct jet-like flow regions in the wake of a swimming polychaete worm (Hesselberg 2006). In the first section of this thesis, this flow pattern is studied in greater detail using a high resolution particle image velocimetry (PIV) technique. A small region close to the wave crest of the undulating worm is recorded and the fluid velocity vector fields are plotted. The close-up PIV results show how the jet-like fluid pattern is formed due to the action both of a single sweeping parapodium and to the interaction between adjacent parapodia, proving for the first time that Gray’s (1939) explanation of the propulsion mechanics is in fact correct. The second part of this thesis is focused on the pumping action of the polychaete worm, a behaviour adopted by the worms to create a flow of nutrients through their burrows. Particle image velocimetry (PIV) experiments were performed on tethered polychaete worms, Nereis diversicolor. The tethered worms moved in a gait which was different from that of freely swimming ones. They used a much smaller body wave amplitude, pumping liquid with very high efficiency by cooperative movement of their body and parapodia. In the third part of the thesis, a mechanical model was designed and built. The model consisted of a series of paddle units. Each paddle was driven by a servo motor. Breugem (2008) did a CFD simulation of the paddle model. Similar fluid patterns were generated by the physical model. Reversed flow was found at low Reynolds number (Re) and higher Re situations. The flow direction could be controlled by simply adjusting the beating frequency of paddles. The mechanical model is not sufficient to mimic the pumping locomotion of the worms due to absence of an undulatory movement. The pumping efficiency is low compared to pumping worms.

Double-Enveloping Reducers are used widely in various industries. In this study, a procedure is developed to analyze the geometric and kinematic properties of such a rotational reducer. In the mechanism, the globoidal worm profile is derived by using the sweeping method and the profile of the globoidal worm wheel is obtained by employing the screw theory. Based on Standards of the American Gear Manufacturers Association (AGMA 6030-C87), the involved parameters in designing and analyzing the reducer are revealed. Finally, the transmission errors based on tooth the contact analysis (TCA) are also reported.

There seems to be more security events happening on the network nowadays, so the administrators have to be able to find the malicious activities in progress as soon as possible in order to launch effective and efficient countermeasures. The Network administrators need to monitor the networks through collecting real time traffic measurement data on their networks, but they might find that the data gathered seems to be too little or too much detail. SNMP-based tools traditionally adopted most often give too little. However, packet sniffing tools investigate too much, so that the performance is sacrificed, especially on a large network with heavy traffic. Flows are defined as a series of packets traveling between the two communicating end hosts. Flow profiling functionality is built into most networking devices today, which efficiently provide the information required to record network and application resource utilization. Flow strikes a balance between detail and summary. NetFlow is the de facto standard in flow profiling. We introduce¡A describe¡Aand investigate its features, advantages, and strengths. Many useful flow-related tools are freely available on the Internet. A mechanism is proposed to make use of the flow logs to monitor the network effectively and efficiently. Through verification, it is believed that using flow logs can benefit the network administrator so much. The administrators can use them for timely monitoring, DoS and worm propagation detection, forensics et al.

DNA bending plays a vital role in numerous cellular activities such as transcription, viral packaging, and nucleosome formation. Therefore, understanding the physics of DNA bending at the length scales relevant to these processes is one of the main keys to the quantitative description of life. However, previous studies provide a divided picture on how DNA should be modeled in strong bending condition relevant to biology. My thesis is devoted to answering how far an elastic rod model can be applied to DNA. We consider several subtle features that could potentially lead to the break-down of the worm-like chain model, such as local bendedness of the sequence and large bending angles. We used single-molecule Fluorescence Resonance Energy Transfer to track looping and unlooping of single DNA molecules in real time. We compared the measured looping and unlooping rates with theoretical predictions of the worm-like chain model. We found that the intrinsic curvature of the sequence affects the looping propensity of short DNA and an extended worm-like chain model including the helical parameters of individual base pairs could adequately explain our measurements. For DNA with random sequence and negligible curvature, we discovered that the worm-like chain model could explain the stability of small DNA loops only down to a critical loop size. Below the critical loop size, the bending stress stored in the DNA loop became less sensitive to loop size, indicative of softened dsDNA. The critical loop size is sensitive to salt condition, especially to magnesium at mM concentrations. This finding enabled us to explain several contrasting results in the past and shed new light on the energetics of DNA bending.

Lipid-detergent systems are interesting to study, as the two amphiphiles have very different spontaneous curvature, however readily form mixed micelles in solution. These micelles can be shorter cylindrical micelles or long worm-like micelles. For such a system the size of the micelles varies strongly with solute conditions, being dependent on the total amount of amphiphile in solution, as well as, the lipid to detergent ratio in the micelles. Although the broad phase behaviour of such systems has been studied and is relatively well understood, there are still many open questions remaining. Some of the questions that motivated the work presented are: how the length and composition of the micelles varies within the micellar region, and how the micelles grow? The biologically interesting system under study is lecithin and bile salt, where the equilibrium sizes were experimentally determined for different samples within the micellar region. A model, combining the length of the micelles, with the concentrations of lecithin and bile salt in the system is presented, and is used to calculate the composition of the micelles at equilibrium. The kinetics of the growth of the micelles after a pertubation causing a shift in the equilibrium size has not been studied in detail before. The kinetics of the system are studied using a stopped flow setup, which I specifically designed for neutron scattering experiments. The stopped flow setup allows for the measurement to start 200ms after the initial mixing of the two liquids, after dilution of a solution the micelles relax to a new longer length. The kinetics of this relaxation were studied as a function of the initial and final size of the micelles, as well as, the ionic strength of the solution. The micelles were found to grow through coalescence, where the rate of growth seems to be constant for different sizes of micelles and the time taken for the relaxation depends on the difference between the final and initial lengths of the micelles. The rate of growth is strongly influenced through changing the ionic strength of the solution, indicating the importance of an electrostatic barrier to the fusion of micelles.

Elk (Cervus elaphus) were historically present throughout Kentucky, but were extirpated by the mid 19th century. Kentucky Department of Fish and Wildlife Resources initiated elk reintroduction efforts in 1997, resulting in a self-sustaining population. I designed this project to study the effects of a parasitic nematode, meningeal worm (Parelaphostrongylus tenuis), on Kentucky’s elk herd. I examined potential maternal transfer of P. tenuis antibodies to elk calves, and investigated the relationship between elk habitat use and meningeal worm infection. I captured neonatal elk in 2004-06, fitted them with VHF transmitters, and collected blood samples for an enzyme-linked immunosorbent assay (ELISA) to determine P. tenuis infection. I monitored animals to determine habitat use, and attempted to recapture each individual to collect a follow-up blood sample. I found substantial rates of maternal meningeal worm antibody transfer (55%) over the course of the study. Neither sex nor predicted birth weight was associated with increased likelihood of obtaining maternal antibodies. Habitat variables associated with P. tenuis infection included herbaceous, shrub, and bare cover types, herbaceous mean core area, forest edge density, and forest mean core area. Confounding variables complicated habitat data analysis, but high rates of maternal P. tenuis antibody transmission suggested that meningeal worm infection does not threaten the long-term viability of the Kentucky elk herd.

Boreal regions account for a significant portion of Canada's landmass and economic resources (e.g., forestry, mining, and oil and gas). The inadvertent release of pollutants from industrial activities within these regions stress the need for realistic ecological risk assessments, which can be attained through the use of standardized soil toxicity test methods. Despite the geophysical and economic significance of boreal regions, standardized soil toxicity test methods applicable to these regions are lacking. To help alleviate this gap in ecotoxicology, the objectives of this thesis included the development and application of a new suite of boreal species for the assessment of contaminants in boreal soils. Specifically, research was directed towards the development of a new oribatid mite test, using Oppia nitens (C.L. Koch). Oribatid mites represent the most abundant and diverse microarthropod species in forest soils, significantly contributing to nutrient cycling and soil formation processes; however, these organisms are consistently under-represented in soil ecotoxicological assessments. The applicability and limitations of the use of O. nitens were demonstrated such that lethal and sublethal endpoints could be derived from the assessment of soils. The performance of O. nitens across numerous soils varied such that adult survival was unaffected by soil characteristics, however, reproduction was limited by soil organic matter content. An evaluation of the sensitivity of O. nitens, using a model polycyclic aromatic hydrocarbon was also conducted in a standard test soil. Phenanthrene is a common contaminant in soils, and accumulates within organic-rich horizons, within which oribatid mites live. Therefore, the study was designed to examine the toxicity and bioaccumulation potential of phenanthrene to O. nitens, with a comparison of effect to other soil invertebrate species, as presented in the literature. Oppia nitens was susceptible to phenanthrene at levels comparable to other soil invertebrate species, and the bioaccumulation of the phenanthrene increased with increasing exposure concentration, although steady-state was not achieved during the four-week exposure duration. The accumulation was biphasic in nature, likely a result of initial cuticular sorption processes, followed by the contribution of other processes (e.g., dietary uptake). The elimination of the phenanthrene was not complete, in that at the end of the elimination phase, tissue residues were similar to that observed in the initial gradual accumulation (e.g., by cuticular processes). However, the resultant bioaccumulation factors (BAFs) were relatively low, indicative of limited trophic transfer and biomagnification for this species. Following the development of an O. nitens assay, a further study was conducted to compare the sensitivity of O. nitens to other boreal soil invertebrate species, as well as to standard test species. Soil toxicity tests were designed, using field-collected reference and contaminated (petroleum hydrocarbon- and salt-impacted) soils, using an expanded suite of boreal species (plants: Pinus banksiana, Picea glauca, Picea mariana, Populus tremuloides, Calamagrostis canadensis and Solidago canadensis; earthworms: Dendrodrilus rubidus; and springtails: Folsomia nivalis and Proisotoma minuta). The sensitivity of the boreal species was then compared to that of currently published standard soil toxicity test species (agronomic plants: Elymus lanceolatus and Trifolium pratense; earthworms: Eisenia andrei; and springtails: Folsomia candida). Estimated species sensitivity distributions (ESSDs) were generated to determine whether the boreal and standard test battery of species exhibited differences in their overall sensitivity to the contaminated soil. With regards to the petroleum-hydrocarbon impacted soil, the suite of boreal species was more sensitive relative to the suite of standard test species; however, upon exposure to the salt-impacted soils, no differences in sensitivity were evident between the boreal and standard suite of test species. In both soils, the performance of O. nitens was similar to that observed by the collembolan species. The evaluation of boreal species and soils also took into consideration the use of distinct soil horizons. The layering of horizons was feasible from the initial collection to reassembly for testing in the laboratory, and plant growth was unaffected by this design. However, soil invertebrates demonstrated a preference or avoidance tendency for one horizon over another, and as a result, the assessment of individual horizons was recommended for all future testing. The compilation of research presented herein provides the basis for the standardization of ecologically-relevant test species and methods for the assessment of contaminated soils in boreal regions.

Orientador: Alessandro Francisco Talamini do Amarante / Resumo: Na produção animal o planejamento nutricional inadequado desencadeia grandes prejuízos ao sistema produtivo, trazendo consequências adversas aos animais e menores lucros ao criador. Este trabalho teve por objetivo avaliar a influência da suplementação alimentar sobre a imunidade dos cordeiros, biologia e patogenia de Haemonchus contortus e Trichostrongylus colubriformis. Quarenta e quatro cordeiros machos da raça Dorper com aproximadamente quatro meses e 31,5±3,24 kg de peso corporal foram alocados aleatoriamente em quatro dietas à base de feno triturado, Cynodon dactylon (cv. Tyfton), acrescido de 0%, 25%, 50% ou 75% de concentrado. Em cada dieta sete animais foram infectados com 1.000 larvas infectantes (L3) de H. contortus e 1.000 L3 de T. colubriformis a cada três dias ao longo de 12 semanas. Em cada dieta, quatro animais permaneceram como grupo controle, Não-Infectados. Os grupos experimentais foram: 0%-Infectado, 0%-Não-Infectado, 25%-Infectado, 25%-Não-Infectado, 50%-Infectado, 50%-Não-Infectado, 75%-Infectado e 75%-Não-Infectado. Quanto maior a suplementação, menor a contagem de ovos por grama de fezes (OPG) de H. contortus (P < 0,0001), porém sem influência sobre contagem de OPG de T. colubriformis. O número de fêmeas de H. contortus foi maior no grupo 0% infectado que nas demais dietas (P = 0,0052). Em nenhuma fase parasitária de T. colubriformis houve efeito da Dieta (P > 0,05). Animais da dieta 0%-Infectado tiveram menor volume globular (VG) que seu grupo controle... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

VANETs are the essential component of the intelligent transport system, which attract research and industrial interests increasingly. As the multifunctional mobile nodes integrating transporting, sensing, information processing, and wireless communication capabilities, vehicular nodes are facing remarkable security issues and more vulnerable to malware attack than conventional communication nodes. In this thesis, the behavior and the security issues of the worm spreading on VANETs are studied. The approaches of the worm spreading on VANETs are discussed and an infrastructure based worm containment strategy is proposed. The infrastructure based worm containment problem is modeled as minimum contamination problem by introducing the expected contamination degree. Then the existing greedy method is applied to solve the proposed problem in VANETs scenario. After that, the Grid-shrinking Greedy Method and the Simplified Greedy Method are proposed which incorporate the characteristics of road networks and VANETs respectively. Simulation results show the two proposed methods outperform the existing greedy method and the comparison method from both complexity and solution quality aspects.

Polychaetes are among the most abundant and diverse groups in the benthic environment; however, the diversity of marine polychaetes remains underexplored. On coral reef ecosystems, scientists predict 80-90% of species are still undescribed due to low sampling efforts in certain regions and the understudied nature of smaller invertebrates, such as polychaetes. Sabellidae, a prominent family of polychaetes, are known for their widespread distribution and are recognized as an ornamental worm due to their feather-like appendages. Here, we detail the diversity of Sabellidae around the understudied Arabian Peninsula. The Arabian Peninsula is surrounded by diverse marine ecosystems (e.g., coral reefs, seagrass beds) occurring in extreme environmental conditions (e.g., higher seawater temperature and strong seasonal variation). Our samples included 178 sabellids from the Saudi Arabian Red Sea, the Arabian Sea, and the Arabian Gulf. Collected from February 2019 to February 2020, these sabellids were sampled from hard and soft substrate on coral reefs and their associated habitats. We used two molecular markers, the cytochrome c oxidase subunit I (COI) and 16S ribosomal DNA alongside an array of morphological analyses, including widely used characters, meristic counts, and morphometric measurements, to identify seven morphotypes. Environmental and biological information was also recorded to understand more about the ecology of these relatively understudied polychaetes. Our combined morphological and genetic analyses acknowledge the presence of six species from the genera Sabellastarte, Bispira, Branchiomma, and Acromegalomma. Our study identified the existence of potential undescribed species in the region and proposed expanded geographic ranges for three accepted species, Sabellastarte sanctijosephi, Branchiomma luctuosum, and Acromegalomma nechamae. The present work increases the current knowledge about the overall systematics of marine polychaetes in the Arabian Peninsula and ultimately contributes to the reassessment of the family’s biogeography.