The beef industry has made tremendous strides in reducing pathogen contamination on carcasses. Multiple antimicrobial interventions have been validated for their use during harvesting. Information in regards to cross-contamination with pathogens in the post-harvest environment is limited. Surrogate microorganisms for enteric pathogens are commonly used to validate antimicrobial interventions and might allow for the simulation of cross-contamination through the post-harvest environment. The purpose of this study was to determine how the post-harvest environment impacts the direct and indirect transmission of pathogens. This was achieved by using fluorescent protein-marked surrogate strains of Escherichia coli O157:H7 and Salmonella spp. from inoculated carcasses to the adjacent ones and to the equipment and facility in three different abattoirs. Thirteen hide-on carcasses were inoculated using a gelatin-based slurry containing three nonpathogenic fluorescent protein-marked strains of E. coli biotype I. In order to determine direct and indirect cross-contamination, inoculated and adjacent carcasses were sampled (300 cm2) during the harvesting process at different stages: after hide opening (AHO), prior to evisceration (PE), after evisceration (AE), after splitting (AS), and after final intervention (AFI). Environmental samples consisting of the floor, walls, and air were tested as well as personal equipment including gloves, boots, and aprons. Equipment including hand knives, air knives, meat hooks, hide puller and split saw were also sampled. Results showed evidence of cross-contamination between inoculated carcasses and the adjacent non-inoculated ones for all abattoirs. Although this occurred in all abattoirs, surrogate counts on carcasses were below detectable levels (<1.4 log CFU/cm2) after antimicrobial interventions. Surrogates were found in low levels for all environmental samples. However surrogate counts from equipment such as knives, split saws, meat hooks, and hide puller were more frequently detected (15 percent) than those found on the floor, air and walls samples (10 percent). In the case of aprons, boots, and gloves, the prevalence of countable surrogate samples was 7 percent.

Overuse of the Interstate and National Highway Systems has led many urban freeways to suffer from recurrent congestion and high crash rates. One method of ameliorating these problems is through the use of Active Traffic Management (ATM). Within ATM, the practice of speed harmonization is well suited to improving safety and reducing delay. In this study, speed harmonization is applied to a segment of Interstate Highway 35, just south of downtown Austin, Texas. First, the need for congestion and safety improvements will be established. Then, the framework of a speed harmonization system will be developed through a synthesis of speed harmonization best practice. Next, the speed harmonization framework will be evaluated for its impact on efficiency through the development of before and after micro-simulation models. Finally, the trajectory files generated from simulation will be analyzed using surrogate safety measures to assess the safety impact of the proposed speed harmonization system. / text

Using microsimulation software, with a focus on VISSIM, the analysis of different applications of merge concepts through delay and safety is presented in this thesis. In order to appropriately draw conclusions and usage trends of different merge concepts from the microsimulation software, early merge, late merge, and signal merge were first explored in a thorough literature review. While focusing primarily on delay, queues, and safety, this thesis essentially provides an introduction to determining the ideal merge concept on freeway work zones for varying roadway configurations, roadway conditions, and user demands, among other factors. In addition to delay and queuing analysis completed using VISSIM, the Federal Highway Administration’s Surrogate Safety Assessment Model (SSAM) was used to address the effects of implementing signal merge on rear-end and lane-change conflicts. Compiling the VISSIM microsimulation outputs and SSAM signal merge safety outputs, general conclusions and decisions were provided. While this thesis provides determinations of ideal merge concepts for a variety of cases, it is important for the next researcher to assess some of the assumptions that were made, to ensure that they would not significantly affect the results and analysis. / text

This thesis examines the Surrogate Country System adopted by WTO members in their antidumping investigations against non-market-economy (NME) countries. In this paper, the Author points out that the existing relevant WTO regulations can easily become importing countries' tool of protectionism. Meanwhile, the obvious legal gap in the WTO laws helps the protectionism by leaving large discretion to importing countries. To reveal the irrationalities of the Surrogate Country System, this paper uses China, a typical NME country, as a sample to display how the system is applied in practice. Then, the paper examines the irrationalities of existing regulations. Towards above issues, the Author puts forward several proposals in Chapter 4. The Author argues for distinguishing transformational countries from NME countries. In cases involving transformational countries, the Author proposes a three-step methodology to calculate the normal value. The Author also provides several strategies for Chinese Government and exporters.

This thesis examines the Surrogate Country System adopted by WTO members in their antidumping investigations against non-market-economy (NME) countries. In this paper, the Author points out that the existing relevant WTO regulations can easily become importing countries' tool of protectionism. Meanwhile, the obvious legal gap in the WTO laws helps the protectionism by leaving large discretion to importing countries. To reveal the irrationalities of the Surrogate Country System, this paper uses China, a typical NME country, as a sample to display how the system is applied in practice. Then, the paper examines the irrationalities of existing regulations. Towards above issues, the Author puts forward several proposals in Chapter 4. The Author argues for distinguishing transformational countries from NME countries. In cases involving transformational countries, the Author proposes a three-step methodology to calculate the normal value. The Author also provides several strategies for Chinese Government and exporters.

Contamination of drinking water sources, such as groundwater, by pathogens (protozoa, bacteria and viruses) is of major concern globally. Due to their small size, mobility and high infectivity, enteric viruses have been a focus of groundwater research. However, the behaviour of enteric viruses in aquifer media is still poorly understood, which is partially attributable to the lack of reliable surrogates for these viruses. In the study reported in this thesis, a new type of surrogate was characterised and validated for its use in studying virus fate and transport in groundwater. The surrogates developed were composed of 70 nm carboxylated silica nanoparticles, labelled with dsDNA tags for sensitive detection, and coated with selected proteins to mimic the physico-chemical characteristics (size, charge, density) of two enteric viruses, human rotavirus and adenovirus, frequently found in faecal-contaminated groundwater. The selected enteric viruses and a commonly used virus surrogate, the MS2 bacteriophage, were purified and characterised in terms of size, surface charge, hydrophobicity and aggregation. For validation, the characteristics, the adsorption, degradation and transport of the surface-modified nanoparticles and the viruses were investigated in laboratory studies and compared. The characterisation of the viruses and particles revealed that the modified silica nanoparticles resemble the size and negative surface charge of the rotavirus and adenovirus. In general, the nanoparticles were found to be less hydrophobic than the enteric viruses, thus presumably less interactive with hydrophobic media. In contrast, the MS2 bacteriophage was smaller in size than the enteric viruses studied and considerably more hydrophobic implying stronger interactions with hydrophobic media. The surface-modified nanoparticles were found to be more stable and remained more monodispersed over time than the purified enteric viruses. In laboratory studies using simulated groundwater, the DNA-labelled nanoparticles were more stable over time than the rotavirus, the adenovirus or a plasmid DNA on its own. Interestingly, the study revealed that rotavirus was more persistent than the adenovirus over time in terms of degradation and aggregation, however, day light considerably enhanced rotavirus degradation. The adsorption studies revealed strong interactions between the enteric viruses and natural aquifer media (gravel and sand), whereas most of the surface-modified nanoparticles adsorbed weakly to these media. Only the casein-coated nanoparticles adsorbed strongly to the sand. The MS2 adsorbed to the gravel strongly, but weakly to the sand implying different interactions. The studies on virus and nanoparticle adsorption to hydrophobic-coated and non-modified Ottawa sand supported the results of characterisation. Column studies investigating the transport of the viruses and the nanoparticles in gravel and sand showed that even though gravel had high adsorption capacity in the adsorption tests, all viruses and nanoparticles travelled though the gravel columns with little retention, probably due to insufficient interaction time. This highlights the vulnerability of gravel aquifers to virus contamination. Experiments using sand columns showed great differences in the transport of the particles. Results suggested that the recovery of the DNA-labelled nanoparticles was similar to the recovery of the adenovirus, however, their transport pattern was different. The glycoprotein-, the protein A- and the AMBP-coated nanoparticles mimicked the transport pattern and low recovery of the rotavirus. In contrast, the streptavidin- and casein-coated nanoparticles were not recovered, emphasising the great importance of surface structure in particle transport. The results of this study demonstrated the usefulness of protein-coated silica nanoparticles as virus surrogates in groundwater studies. Surface-modified nanoparticles are able to mimic the surface characteristics of viruses. The glycoprotein-, protein A- and AMBP-coated particles were found to be suitable surrogates for rotavirus, whereas the DNA-labelled nanoparticles resembled adenovirus behaviour in hydrophilic media. Using particles with different material, size and protein-coating other pathogens can be modelled as well. Furthermore, these particles are expected to besafe to humans and the environment, thus can be used in a great variety of experiments in environmental research.

Handheld devices are becoming increasingly common, and they have varied range of resources. Mobile Cloud Computing (MCC) allows resource constrained devices to offload computation and use storage capacities of more resourceful surrogate machines. This enables creation of new and interesting applications for all devices. We propose a scheme that constructs a high-performance de-centralized system by a group of volunteer mobile devices which come together to form a resourceful unit (cloudlet). The idea is to design a model to operate as a public-resource between mobile devices in close geographical proximity. This cloudlet can provide larger storage capability and can be used as a computational resource by other devices in the network. The system needs to watch the movement of the participating nodes and restructure the topology if some nodes that are providing support to the cloudlet fail or move out of the network. In this work, we discuss the need of the system, our goals and design issues in building a scalable and reconfigurable system. We achieve this by leveraging the concept of virtual dominating set to create an overlay in the broads of the network and distribute the responsibilities in hosting a cloudlet server. We propose an architecture for such a system and develop algorithms that are requited for its operation. We map the resources available in the network by first scoring each device individually, and then gathering these scores to determine suitable candidate cloudlet nodes. We have simulated cloudlet functionalities for several scenarios and show that our approach is viable alternative for many applications such as sharing GPS, crowd sourcing, natural language processing, etc.

The focus of this research is to provide an efficient approach to deal with computationally expensive Multiobjective Optimization Problems (MOP’s). Typically, approximation or surrogate based techniques are adopted to reduce the computational cost. In such cases, the original expensive objective function is replaced by a cheaper mathematical model, where this model mimics the behavior/input-output (i.e. design variable – objective value) relationship. However, it is difficult to model an exact substitute of the targeted objective function. Furthermore, if this kind of approach is used in an evolutionary search, literally, the number of function evaluations does not reduce (i.e. The number of original function evaluation is replaced by the number of surrogate/approximate function evaluation). However, if a large number of individuals are considered, the surrogate model fails to offer smaller computational cost. / To tackle this problem, we have reformulated the concept of surrogate modeling in a different way, which is more suitable for the Multiobjective Evolutionary Algorithm(MOEA) paradigm. In our approach, we do not approximate the objective function; rather we model the input-output behavior of the underlying MOEA itself. The model attempts to identify the search path (in both design-variable and objective spaces) and from this trajectory the model is guaranteed to generate non-dominated solutions (especially, during the initial iterations of the underlying MOEA – with respect to the current solutions) for the next iterations of the MOEA. Therefore, the MOEA can avoid re-evaluating the dominated solutions and thus can save large amount of computational cost due to expensive function evaluations. We have designed our approximation model as a variation operator – that follows the trajectory of the fronts and can be “plugged-in” to any kind of MOEA where non-domination based selection is used. Hence it is termed– the “Pareto-Following Variation Operator (PFVO)”. This approach also provides some added advantage that we can still use the original objective function and thus the search procedure becomes robust and suitable, especially for dynamic problems. / We have integrated the model into three base-line MOEA’s: “Non-dominated Sorting Genetic Algorithm - II (NSGA-II)”, “Strength Pareto Evolutionary Algorithm - II (SPEAII)”and the recently proposed “Regularity Model Based Estimation of Distribution Algorithm (RM-MEDA)”. We have also conducted an exhaustive simulation study using several benchmark MOP’s. Detailed performance and statistical analysis reveals promising results. As an extension, we have implemented our idea for dynamic MOP’s. We have also integrated PFVO into diffusion based/cellular MOEA in a distributed/Grid environment. Most experimental results and analysis reveal that PFVO can be used as a performance enhancement tool for any kind of MOEA.

Viral transmission from the environment can occur via fomites, but there is uncertainty about which factors most affect viral persistence on fomites. Children are a population highly susceptible to viral infection, and sharing common fomites like toys may spread infection. The objective of this research was to assess the survival of enveloped viruses on the surfaces of children’s toys, using bacteriophage ϕ6 as a surrogate for enveloped human viruses. The survival of infectious ϕ6 virions was observed over a 24 hour period at 22°C and relative humidities of 40% & 60%. On the surface of children’s toys, ϕ6 was better able to persist at 60% RH (log10 reduction< 2 log10) over a 24 hour period than it was at 40% RH (log10 reduction> 6 log10). If ϕ6 virus persists on toy material for up to 24 hours, then viral transmission via shared fomites is certainly significant.

Orientador: José Senhorini / Abstract: The aim of this study was to describe a procedure for sampling, reproduction, and first feeding of the Neotropical catfish Pseudopimelodus mangurus. Wild adult P. mangurus specimens were collected in the Mogi Guassu river, and subsequently, were induced to spawn in laboratory conditions. After hand-stripping the females, the average weight of the oocytes was 143 ± 1.66 g, having an average of 718 ± 49.802 oocytes g-1. The diameter of zygotes was about 1226.354 ± 47.719 µm nonhydrated to 1761.256 ± 26.412 µm after hydration. The fertilization rates were 98.00 ± 0.63%, and the hatching rate were 68.94 ± 11.83%. Three days after hatching, the larvae started exogenous feeding. First feedings were made with 6 different treatments, in which the best results arose with sequential feeding with artemia nauplii, Astyanax altiparanae, and Prochilodus lineatus larvae. This condition resulted in a growth rate of 2012.795 ± 44.891 µm by the tenth day of experiment, higher survival rate (65 ± 0.09%), and a lower cannibalism rate 14 ± 0.03% on the tenth day after exogenous feed. The data obtained in this study is important for reproductive biotechniques and mass production of the endangered catfish P. mangurus. / Mestre