989 resultados para Statistical methodologies
Resumo:
Rapid and specific detection of foodborne bacteria that can cause food spoilage or illness associated to its consumption is an increasingly important task in food industry. Bacterial detection, identification, and classification are generally performed using traditional methods based on biochemical or serological tests and the molecular methods based on DNA or RNA fingerprints. However, these methodologies are expensive, time consuming and laborious. Infrared spectroscopy is a reliable, rapid, and economic technique which could be explored as a tool for bacterial analysis in the food industry. In this thesis it was evaluated the potential of IR spectroscopy to study the bacterial quality of foods. In Chapter 2, it was developed a calibration model that successfully allowed to predict the bacterial concentration of naturally contaminated cooked ham samples kept at refrigeration temperature during 8 days. In this part, it was developed the methodology that allowed the best reproducibility of spectra from bacteria colonies with minimal sample preparation, which was used in the subsequent work. Several attempts trying different resolutions and number of scans in the IR were made. A spectral resolution of 4 cm-1, with 32 scans were the settings that allowed the best results. Subsequently, in Chapter 3, it was made an attempt to identify 22 different foodborne bacterial genera/species using IR spectroscopy coupled with multivariate analysis. The principal component analysis, used as an exploratory technique, allowed to form distinct groups, each one corresponding to a different genus, in most of the cases. Then, a hierarchical cluster analysis was performed to further analyse the group formation and the possibility of distinction between species of the same bacterial genus. It was observed that IR spectroscopy not only is suitable to the distinction of the different genera, but also to differentiate species of the same genus, with the simultaneous use of principal component analysis and cluster analysis techniques. The utilization of IR spectroscopy and multivariate statistical analysis were also investigated in Chapter 4, in order to confirm the presence of Listeria monocytogenes and Salmonella spp. isolated from contaminated foods, after growth in selective medium. This would allow to substitute the traditional biochemical and serological methods that are used to confirm these pathogens and that delay the obtainment of the results up to 2 days. The obtained results allowed the distinction of 3 different Listeria species and the distinction of Salmonella spp. from other bacteria that can be mistaken with them. Finally, in chapter 5, high pressure processing, an emerging methodology that permits to produce microbiologically safe foods and extend their shelf-life, was applied to 12 foodborne bacteria to determine their resistance and the effects of pressure in cells. A treatment of 300 MPa, during 15 minutes at room temperature was applied. Gram-negative bacteria were inactivated to undetectable levels and Gram-positive showed different resistances. Bacillus cereus and Staphylococcus aureus decreased only 2 logs and Listeria innocua decreased about 5 logs. IR spectroscopy was performed in bacterial colonies before and after HPP in order to investigate the alterations of the cellular compounds. It was found that high pressure alters bands assigned to some cellular components as proteins, lipids, oligopolysaccharides, phosphate groups from the cell wall and nucleic acids, suggesting disruption of the cell envelopes. In this work, bacterial quantification and classification, as well as assessment of cellular compounds modification with high pressure processing were successfully performed. Taking this into account, it was showed that IR spectroscopy is a very promising technique to analyse bacteria in a simple and inexpensive manner.
Resumo:
This dissertation introduces several methodological approaches which integrate a proposed coastal management model in an interdisciplinary perspective. The research presented herein is displayed as a set of publications comprising different thematic outlooks. The thesis develops an integrated coastal geoengineering approach which is intrinsically linked to the studied maritime environments. From sandy coasts and marine works to rocky platforms and sea cliffs, this study includes field work between Caminha – Figueira da Foz (NW Portugal) and Galicia (NW Spain). The research also involves an analysis and geological-geotechnical characterisation of natural rock (armourstone) and artificial units (concrete blocks) applied to coastal structures. The main goal is to contribute to the characterisation and re-evaluation of georesources and to determine armourstone suitability and availability from its source (quarry). It was also important to diagnose the geomaterials in situ concerning their degradation/deterioration level on the basis of the current status of the coastal protection works in order to facilitate more efficient monitoring and maintenance, with economic benefits. In the rocky coast approach the coastal blocks were studied along the platform, but also the geoforms were studied from a coastal morphodynamics point of view. A shoreline evolution analysis was developed for sandy coasts through Digital Shoreline Analysis System (DSAS) extension. In addition, the spatial and statistical analysis applied to sea cliffs allowed the establishment of susceptibility zones to erosion and hazardous areas. All of these studies have different purposes and results however, there is a common denominator – GIS mapping. Hence, apart from the studied coastal environment, there is an integrated system which includes a sequence of procedures and methodologies that persisted during the research period. This is a step forward in the study of different coastal environments by using almost the same methodologies. This will allow the characterisation, monitoring and assessment of coastal protection works, rocky coasts, and shore platforms. With such data, it is possible to propose or recommend strategies for coastal and shoreline management based on several justifications in terms of social, economic, and environmental questions, or even provide a GIS-based planning support system reinforced by geocartographic decisions. Overall the development of the applied cartography embraces six stages which will allow the production of detailed maps of the maritime environment: (1) high-resolution aerial imagery surveys; (2) visual inspection and systematic monitoring; (3) applied field datasheet; (4) in situ evaluation; (5) scanline surveying; and (6) GIS mapping. This thesis covers fundamental matters that were developed over the course of scientific publication and as a consequence they represent the results obtained and discussed. The subjects directly related to the thesis architecture are: (i) cartography applied to coastal dynamics (including an art historical analysis as a tool to comprehend the coastal evolution and the littoral zone); (ii) georesources assessment (the role of cartography in georesources zoning, assessment and armourstone durability); (iii) coastal geoengineering applications and monitoring (Espinho pilot site in NW Portugal as an experimental field); (iv) rocky coast and shore platform studies and characterisation; (v) sandy and mixed environment approaches; (vi) coastal geosciences GIS mapping and photogrammetric surveying (coastal geoengineering); and (vii) shoreline change mapping and coastal management strategies (the CartGalicia Project as an example – NW Spain). Finally, all of these thematic areas were crucial to generate the conceptual models proposed and to shape the future of integrated coastal coastal geoengineering management.
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The South Carolina Department of Probation, Parole and Pardon Services annually publishes a statistical report providing a description of the offender population and the agency's programs.
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The South Carolina Department of Probation, Parole and Pardon Services annually publish a statistical report providing a description of the offender population and the agency's programs.
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The South Carolina Department of Probation, Parole and Pardon Services annually publish a statistical report providing a description of the offender population and the agency's programs.
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The South Carolina Department of Probation, Parole and Pardon Services annually publish a statistical report providing a description of the offender population and the agency's programs.
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The South Carolina Department of Probation, Parole and Pardon Services annually publish a statistical report providing a description of the offender population and the agency's programs.
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The South Carolina Budget and Control Board, Office of Research and Statistics annually published Statistical Abstracts, a comprehensive, single-source reference of demographic and economic data pertinent to the state. This publication is now an online publication by the South Carolina Revenue and Fiscal Affairs Office.
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The South Carolina Budget and Control Board, Office of Research and Statistics annually published Statistical Abstracts, a comprehensive, single-source reference of demographic and economic data pertinent to the state. This publication is now an online publication by the South Carolina Revenue and Fiscal Affairs Office.
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The South Carolina Budget and Control Board, Office of Research and Statistics annually published Statistical Abstracts, a comprehensive, single-source reference of demographic and economic data pertinent to the state. This publication is now an online publication by the South Carolina Revenue and Fiscal Affairs Office.
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The South Carolina Budget and Control Board, Office of Research and Statistics annually published Statistical Abstracts, a comprehensive, single-source reference of demographic and economic data pertinent to the state. This publication is now an online publication by the South Carolina Revenue and Fiscal Affairs Office.
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The South Carolina Budget and Control Board, Office of Research and Statistics annually published Statistical Abstracts, a comprehensive, single-source reference of demographic and economic data pertinent to the state. This publication is now an online publication by the South Carolina Revenue and Fiscal Affairs Office.
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The South Carolina Budget and Control Board, Office of Research and Statistics annually published Statistical Abstracts, a comprehensive, single-source reference of demographic and economic data pertinent to the state. This publication is now an online publication by the South Carolina Revenue and Fiscal Affairs Office.
Resumo:
The South Carolina Budget and Control Board, Office of Research and Statistics annually published Statistical Abstracts, a comprehensive, single-source reference of demographic and economic data pertinent to the state. This publication is now an online publication by the South Carolina Revenue and Fiscal Affairs Office.
Resumo:
The South Carolina Budget and Control Board, Office of Research and Statistics annually published Statistical Abstracts, a comprehensive, single-source reference of demographic and economic data pertinent to the state. This publication is now an online publication by the South Carolina Revenue and Fiscal Affairs Office.