The goal of this research is to improve an IDS so that the percentage of true positives is high, an organisation can cut time and cost and use its resources in a more optimal way. This research goal was to prove that the precision of an intrusion detection system (IDS), in terms of producing lower rate of false positives or higher rate of true alerts, can be achieved by parsing indicators of compromise (IOC) to gather information, that combined with system-specific knowledge will be a solid base for manual fine-tuning of IDS-rules. The methodology used is Design Science Research Methodology (DSRM) because it is used for research that aims to answer an existing problem with a new or improved solution. A part of that solution is a proposed process for tuning of an arbitrary intrusion detection system. The implemented and formalized process Tuned Intrusion Detection System (TIDS) has been designed during this research work, aiding us in presenting and performing validation tests in a structured and robust way. The testbed consisted of a Windows 10 operating system and a NIDS implementation of Snort as an IDS. The work was experimental, evaluated and improved regarding IDS rules and tools over several iterations. With the use of recorded data traffic from the public dataset CTU-13, the difference between the use of tuned versus un-tuned rules in an IDS was presented in terms of precision of the alerts created by the IDS. Our contributions were that the concept holds; the precision can be improved by adding custom rules based on known parameters in the network and features of the network traffic and disabling rules that were out of scope. The second contribution is the TIDS process, as designed during the thesis work, serving us well during the process.

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<p>The osmorespiratory compromise is the trade-off between high gill permeability for oxygen uptake and low gill permeability for conservation of ions in fish. The fundamental purpose of this study was to examine facets of the osmorespiratory compromise in freshwater fish under conditions of extended exercise and acute hypoxia, in light of previous research identifying very different gill morphometric and ionoregulatory modifications in the hypoxia-tolerant Amazonian oscar (<em>Astronotus ocellatus</em>) and the hypoxia-intolerant rainbow trout (<em>Oncorhynchus mykiss</em>). A technique using [³H]polyethylene-4000 ([³H]PEG-4000) for branchial paracellular permeability measurement was developed, and then applied to investigate the osmorespiratory compromise during extended swimming. Methods were developed to overcome the challenges of renal [³H]PEG-4000 loss, respirometer surface adsorption, and freshwater drinking of the chemical. In both trout and oscar, corrections were employed for these sources of error – leading to findings that in both species, branchial [³H]PEG-4000 permeability was not rectified and freshwater drinking was quite high. In both species, during an 8-h swim (1.2BL/s), oxygen consumption rate increased by 75-90%; drinking rate remained high but did not increase. Branchial paracellular permeability increased by 61% during exercise in trout but remained constant in oscar. The methods developed here can be widely applied to future studies of branchial paracellular permeability.</p> <p>Unidirectional fluxes (by ²²Na) of sodium, and net fluxes of potassium, ammonia, and urea were observed during a 2-h nomoxia:2-h hypoxia (30% O₂ saturation):2-h normoxic recovery protocol – to identify adaptive trends across phylogenies and/or environments in North and South American teleosts. Strategies for coping with hypoxia appeared to be environmentally, rather than phylogenetically linked, since both the oscar (perciform) and the tambaqui (<em>Colossoma macropomum</em> – characiform) displayed characteristic permeability reduction (of apparent transcellular origin); both frequently encounter severe hypoxia in their natural habitat. Two North American perciforms, pumpkinseed (<em>Lepomis gibbosus</em>) and bluegill sunfish (<em>Lepomis macrochirus</em>) which live in less hypoxic environments, increased branchial ion leakage as in the hypoxia-intolerant trout. Four Amazonian tetra species (all characiformes: <em>Paracheirodon axelrodi, Hemigrammus rhodostomus, Moenkausia diktyota,</em> <em>Hyphessobrycon bentosi rosaceus</em>) which experience intermediate hypoxia in their native Rio Negro presented variable responses. Finally, during a 4-h swim at1.2BL/s, branchial ion fluxes were not reduced but elevated in oscar, indicating that ionoregulation in this species occurs primarily transcellularly, and that adaptive strategies to one manifestation of the osmorespiratory compromise (hypoxia) may not apply to another (exercise).</p> / Master of Science (MSc)

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Objetivo: Comparar as imagens obtidas por meio da sinuscopia virtual com aquelas adquiridas por meio da tomografia computadorizada helicoidal, quando da interpretação dos comprometimentos sinusais, considerando as opiniões dos médicos otorrinolaringologistas e radiologistas odontológicos, com a finalidade de validação do método da sinuscopia virtual. Métodos: Foram utilizadas informações obtidas por meio da observação de imagens de 20 casos pertencentes ao arquivo docente, da Unidade de Imagens Dento-Maxilo-Facial da Clínica Felix Boada, em Caracas-Venezuela. Os referidos casos apresentaram imagens adquiridas por meio da tomografia computadorizada helicoidal e imagens obtidas por meio da sinuscopia virtual. As imagens foram analisadas por 2 grupos de observadores, 10 médicos otorrinolaringologistas e 10 radiologistas odontológicos, que responderam a um questionário previamente elaborado. Resultados: Os resultados foram avaliados pelos testes estatísticos de média aritmética, mediana, desvio padrão, análise de médias, percentuais globais, teste não–paramétrico de Kruskal-Wallis e teste não-paramétrico de Wilcoxon. Conclusões: Para os médicos otorrinolaringologistas e radiologistas odontológicos faz-se importante, a associação das imagens obtidas por meio da sinuscopia virtual com as imagens axiais obtidas por meio da tomografia computadorizada helicoidal na interpretação de um comprometimento sinusal. Os radiologistas odontológicos acharam que as imagens axiais obtidas por meio da tomografia computadorizada helicoidal já eram esclarecedoras, na avaliação dos casos, embora também recomendassem a sinuscopia virtual. Nos casos considerados fáceis, a aplicação da sinuscopia virtual foi evidente, porém nos casos difíceis não contribuiu. A sinuscopia virtual isoladamente não oferece condições para a conclusão do diagnóstico de uma afecção sinusal. / Purpose: To compare the images obtained by means of virtual sinuscopy with those formed by means of helical computerized tomography during the interpretation of sinusal compromise taking into consideration the opinions of otorhinolaryngologists and odontological radiologists aiming to validate the method of virtual sinuscopy. Methods: Information obtained through the observation of images of 20 cases belonging to the professorial file, of the Dental – Maxillo - Facial Unit of Images of Félix Boada Clinic in Caracas–Venezuela were used. The cases mentioned above showed images formed by means of the helical computerized tomography and images formed by means of the virtual sinuscopy. The images were analysed by 2 groups of observers, 10 otorhinolaryngologists and 10 odontological radiologists who answered a questionnaire previously prepared. Results: The results were appraised through statistical tests of arithmetic average, median, standard deviation, average analysis, global percentile, Kruskal-Wallis non-parametric test and Wilcoxon non-parametric test. Conclusions: To the otorhinolaryngologists and odontological radiologists it is important, the association of the images obtained by means of the virtual sinuscopy with the axial images formed by means of helical computerized tomography in the interpretation of a sinusal compromise. The odontological radiologists thought the axial images formed by means of the helical computerized tomography were already elucidatory, for the evaluation of the cases although they also recommended the virtual sinuscopy. In the cases regarded as easy ones, the application of the virtual sinuscopy was evident, but in the difficult cases it didn’t contribute. The virtual sinuscopy used singly doesn’t offer conditions for a diagnostic conclusion of the sinusal affection.

Goldfish undergo an adaptive morphological change in their gills involving the reversible growth and loss of a mass of cells (interlamellar cell mass, ILCM) in between the lamellae depending on oxygen demand, which can be altered by the environment or metabolic demands of the individual. The ILCM contributes to decreased passive Na+ efflux across the gill. Active uptake is maintained by the re-distribution of the ionocytes expressing Na+-uptake relevant genes (NHEs and H+-ATPase) to the outer edge of the ILCM where they can establish contact with the external environment and/or lamellar epithelium. This adaptation is thought to be partly responsible for the extreme anoxia tolerance demonstrated by goldfish, which they experience on a seasonal basis living in a pond environment. Hypoxia and hypercapnia are frequently encountered in such freshwater environments and as such, the effect of the ILCM on the capacity for acid-base regulation was evaluated. Differences in the time course of acid excretion to the environment without effect on systemic pH regulation were likely the result of the ILCM.

This study presents the investigation of the career transition experience of immigrant skilled workers with a focus on their experiences with career compromise and the coping strategies that they used. The grounded theory approach of qualitative analysis method was used to analyze 20 interview transcripts with participants who had received their education/training and had at least 1 year of work experience prior to immigrating to Canada. The interviews revealed that the career transition journeys of immigrant skilled workers were thwarted with acculturation and career-seeking barriers, which made their career transition experiences quite compromising. The findings support the notion of positive compromise whereby the participants utilized their human agency and open-mindedness to deal with their career compromise. An immigrant vocational theory and an immigrant career compromise theory are proposed. Practical implications and future research directions are discussed.

This study presents the investigation of the career transition experience of immigrant skilled workers with a focus on their experiences with career compromise and the coping strategies that they used. The grounded theory approach of qualitative analysis method was used to analyze 20 interview transcripts with participants who had received their education/training and had at least 1 year of work experience prior to immigrating to Canada. The interviews revealed that the career transition journeys of immigrant skilled workers were thwarted with acculturation and career-seeking barriers, which made their career transition experiences quite compromising. The findings support the notion of positive compromise whereby the participants utilized their human agency and open-mindedness to deal with their career compromise. An immigrant vocational theory and an immigrant career compromise theory are proposed. Practical implications and future research directions are discussed.

Goldfish undergo an adaptive morphological change in their gills involving the reversible growth and loss of a mass of cells (interlamellar cell mass, ILCM) in between the lamellae depending on oxygen demand, which can be altered by the environment or metabolic demands of the individual. The ILCM contributes to decreased passive Na+ efflux across the gill. Active uptake is maintained by the re-distribution of the ionocytes expressing Na+-uptake relevant genes (NHEs and H+-ATPase) to the outer edge of the ILCM where they can establish contact with the external environment and/or lamellar epithelium. This adaptation is thought to be partly responsible for the extreme anoxia tolerance demonstrated by goldfish, which they experience on a seasonal basis living in a pond environment. Hypoxia and hypercapnia are frequently encountered in such freshwater environments and as such, the effect of the ILCM on the capacity for acid-base regulation was evaluated. Differences in the time course of acid excretion to the environment without effect on systemic pH regulation were likely the result of the ILCM.