Made available in DSpace on 2016-08-10T10:38:43Z (GMT). No. of bitstreams: 1 RAQUEL VAZ RESENDE.pdf: 8228076 bytes, checksum: 2434f1bf0bafb200c6e01978c59427a6 (MD5) Previous issue date: 2013-02-08 / The importance of scientific proof for the current Brazilian justice system is notorious. Article 158 of the CPC provides that when the offense is a trace essential examination of the corpus delicti. But many fingerprints arriving in section showdown Police Technician - Scientific Goiás, do not present conditions for analysis are blurred or incomplete, and thus unusable. The possibility of extracting DNA of these appears as an option in criminal investigations. The present study detected by light microscopy, scaly epidermal cells in 98% of the fifty sheets containing fingerprints subjected to Leishman stain, and the amount varied from fifteen to seven hundred and seventy cells per slide. After DNA extraction sixty-nine samples, deposited on five different media (aluminum, wood, paper, plastic and glass) were obtained concentrations ranging from 0.3 ng / uL to 25.4 ng / uL. Analyzing the concentrations of each surface separately observed that wood was the one with the highest average concentration of DNA (10.67 ng / uL), while paper and plastic had equal means and the lowest (5.92 ng / uL) . Comparing the media by student t test, we found three statistically significant analysis, the largest difference was observed between the surfaces of wood and paper (p = 0.001). When extracting DNA prints developed with ninhydrin or impregnated by black powder, concentration obtained in 70% of samples with ninhydrin and 60% of samples with dust. This study corroborates several studies have shown that it is possible to extract DNA from surfaces that have been touched by the hands of just one person. Our experiments also showed obtaining a higher concentration in the porous surfaces in relation to smooth surfaces and that using ninhydrin and black powder also allow the extraction of said genetic material. / A importância da prova científica para o atual sistema de justiça brasileiro é notória. O artigo 158 do CPP determina que quando a infração deixar vestígios será indispensável o exame do corpo de delito. Porém, muitas impressões digitais que chegam à seção de confronto da Polícia Técnico - Científica de Goiás, não apresentam condições de análises por estarem borradas ou incompletas, sendo assim, inutilizadas. A possibilidade de extrair DNA destas surge como uma opção nas investigações criminais. O presente estudo detectou, à microscopia óptica, células descamativas da epiderme em 98% das cinquenta lâminas contendo impressões digitais submetidas à coloração de Leishman, sendo que a quantidade variou de quinze a setecentos e setenta células por lâmina. Após a extração de DNA de sessenta e nove amostras, depositadas em cinco suportes diferentes (alumínio, madeira, papel, plástico e vidro) foram obtidas concentrações que variaram entre 0,3 ng/µL a 25,4 ng/µL. Analisando as concentrações de cada superfície separadamente observamos que a madeira foi a que apresentou a maior concentração média de DNA (10,67 ng/µL), enquanto que o papel e plástico apresentaram médias iguais e as menores (5,92 ng/µL). Na comparação entre os suportes pelo teste t student, encontramos três análises estatisticamente significativas, sendo a maior diferença foi observada entre as superfícies de madeira e papel (p = 0,001). Ao extrair DNA de impressões reveladas com ninidrina ou impregnadas pelo pó preto, obtivemos concentração em 70% das amostras com ninidrina e 60% das amostras analisadas com pó. O presente trabalho corrobora com vários estudos que já demonstraram ser possível extrair DNA de superfícies que foram simplesmente tocadas pelas mãos de uma pessoa. Nossos experimentos demonstraram, ainda, a obtenção de uma maior concentração nas superfícies porosas em relação às superfícies lisas e que o uso de ninidrina e pó de cor preta também permitem a extração do referido material genético.

Made available in DSpace on 2017-07-21T14:42:29Z (GMT). No. of bitstreams: 1 Rodrigo Moreira Caetano Pinto.pdf: 2408271 bytes, checksum: dd930813a70ef7a000eb483899333bfd (MD5) Previous issue date: 2014-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The use of natural products with therapeutic or nutraceutical purposes is growing in the brazilian society, due the easily access to this. However, the indiscriminate use or use of wrongly identified species represent a risk of the user. Thus, phytochemical and pharmacological studies, and the development of analytical methods to the quality control of these products are important actions to ensure the reliability of them. Thus, it is necessary a consistent quality evaluation of vegetal raw materials, that endorse its identity and quality. The erva-mate (Ilex paraguariensis A.St.-Hil. - Aquifoliaceae) is a south brazilian native specie, heavily consumed as stimulant drink. This plant have presented a great economic value as raw material, due the growing interest of the cosmetic and pharmaceutical industries, mainly arising the stimulant, antioxidant and lipolytic potential. The high performance liquid chromatography (HPLC) is a fast and efficient method to the qualitative and quantitative evaluation of medicinal plants and its extracts. The development of analytical methods to quality control of these materials is a necessary action for the pharmaceutical, cosmetic and food industries. To the industries, the Quality by Design approach – that proposes the creation of a design of experiments (DOE) that evaluate simultaneously many relevant factors to the separation efficiency – is an alternative to the classic optimization of HPLC methods, because allows the efficient evaluation of more variables in a short time. In this sense, the aim of this work was realize a factorial study (QbD-DOE) of the main variables that may affect the optimization of a chromatographic method to vegetal extracts, and proposes the development of an analytical method. Were analyzed many relevant factors to the resolution of the chromatographic bands. In a first step, were evaluated the stationary phase, pH range, organic modifier type and the gradient time. In a second stage, was evaluated de pH value, final % of organic modifier, temperature and flow rate. The developed method was used to the evaluation of chemical characteristics of seven commercial samples of erva-mate obtained in the market of Ponta Grossa. The fingerprint was employed in a chemometric study, that allowed classify the samples according the chemical profiles, arising of plantation place, processment and extractor solvent. Yet, the obtained chromatographic run enabled the quantitative analysis of three chemical markers (chlorogenic acid, caffeine and theobromine). The contents of the markers founded by the validated method in the evaluated samples were different between aqueous (A) and hydroethanolic (H) extracts, due the differences on extraction potential of these solvents/procedures. The biggest content of caffeine were founded in the sample 5 (92.7 mg/100 g of dry leaves (A) and 349.19 mg/100g (H)). The same sample presented the least content of theobromine, in hydroethanolic extract (45.88 mg/100g), probably because the both xanthines are sourced of the same biosynthetic route. The chlorogenic acid were founded in highest proportion in the sample 2 (388.15 mg/100g (H) and 110.42 mg/100g (H)). The findings of this study reinforce the use of liquid chromatography as an analytical method, that associated to statistical tools may increase the strategies of erva-mate quality control, as vegetal raw material. / A utilização de produtos naturais com fins terapêuticos ou nutracêuticos é crescente na sociedade brasileira devido à facilidade de acesso a estes. Entretanto o uso indiscriminado ou sem uma correta identificação da espécie vegetal que se está utilizando pode se apresentar como um risco ao usuário. Desta forma estudos fitoquímicos, farmacológicos e principalmente o desenvolvimento de métodos analíticos de controle da qualidade destes produtos e seus extratos se constituem em ações importantes para se garantir a confiabilidade dos mesmos. Desta forma, é necessário que a avaliação da qualidade de matérias-primas vegetais seja consistente e respalde sua identidade e qualidade. A erva-mate (Ilex paraguariensis A.St.-Hil. - Aquifoliaceae) é uma espécie vegetal nativa do sul do Brasil, muito consumida como bebida estimulante e vem se apresentando como uma matéria prima de grande valor econômico devido ao crescente interesse das indústrias de medicamentos, cosméticos e alimentos em decorrência principalmente do seu potencial antioxidante, estimulante e lipolítico. A Cromatografia Líquida de Alta Eficiência (CLAE) é um método rápido e eficiente para a avaliação qualitativa e quantitativa de plantas medicinais e seus extratos e o desenvolvimento de métodos analíticos para avaliação da sua qualidade se constitui em uma ação necessária a ser empregada no controle de qualidade de indústrias farmacêuticas, cosméticas e alimentícias. Para as indústrias, a abordagem Quality by Design – que propõe a criação de um desenho experimental que avalia simultaneamente múltiplos fatores relevantes para a eficiência da separação – se constituí em uma alternativa de estudo à otimização clássica de métodos por CLAE, pois permite que mais variáveis sejam avaliadas em um menor tempo e com maior eficiência. Desta forma, foi objetivo deste trabalho realizar um estudo fatorial das principais variáveis que podem interferir na otimização de um método cromatográfico para extratos vegetais e assim propor o desenvolvimento de um método analítico. Num primeiro momento, foram avaliadas a fase estacionária, faixa de pH, tipo de modificador orgânico e o tempo de corrida. Numa segunda etapa, foram avaliados o valor exato de pH, a concentração final do modificador orgânico, a temperatura e o fluxo. O método desenvolvido foi utilizado para avaliação das características químicas de sete amostras comerciais de erva mate obtidas no comércio da cidade de Ponta Grossa. O cromatograma fingerprint foi utilizado para a realização de um estudo quimiométrico que permitiu classificar as amostras quanto a semelhanças e diferenças químicas decorrentes da região de plantio, procedimento de processamento empregado e solvente extrator usado. Ainda, a corrida cromatográfica obtida possibilitou avaliação quantitativa de três marcadores químicos (ácido clorogênico, cafeína e teobromina). Os teores dos marcadores encontrados nas amostras avaliadas, através do método cromatográfico validado variaram entre as amostras de extrato aquoso (A) e hidroalcoólico (H), devido à diferença de potencial extrativo entre esses solventes/procedimentos. O maior teor de cafeína foi encontrado na amostra 5 (92, 7 mg/100 g de folhas secas (A) e 349,19 mg/100g (H)). A mesma amostra apresentou o menor teor de teobromina no extrato hidroalcoólico (45,88 mg/100g), provavelmente porque as duas xantinas dividem a mesma rota de biossíntese. O ácido clorogênico foi encontrado em maior proporção na amostra 2 (388,15 mg/100g (H) e 110,42 mg/100g (A)). Os achados deste estudo reforçam o uso da cromatografia líquida, como um método analítico que associado a ferramentas estatísticas possibilitam incrementar as estratégias de controle de qualidade da erva-mate enquanto matéria-prima vegetal.

Orientador: Wagner Vilegas / Resumo: Apesar dos diversos relatos do uso de Rhipsalis Gaërtn (Cactaceae) por populações tradicionais no tratamento de uma gama de enfermidades, há pouquíssimos estudos fitoquímicos com esse grupo de cactos e por vezes estes são superficiais, apenas indicando a possível presença de algumas classes de produtos naturais. Ademais, estudos avaliando a atividade biológica de Rhipsalis são escassos. Neste viés, este trabalho objetivou investigar a composição química do gênero Rhipsalis e avaliar possíveis atividades ligadas à sua composição, subsidiando desta forma seu uso popular. Esta dissertação foi dividida e organizada da seguinte forma: a primeira parte apresenta uma introdução geral sobre plantas medicinais e sua importância, assim como uma revisão sobre estudos fitoquímicos em Cactaceae. Em seguida, foram redigidas três seções: na primeira, investigamos a composição química de Rhipsalis teres (Vell.) Steud identificando 5 saponinas derivadas do ácido oleanólico, 2 flavonoides C-glicosilados derivados da apigenina e 2 ácidos fenólicos; na segunda, investigamos a composição química do gênero Rhipsalis identificando 28 saponinas cujo core é o ácido oleanólico e 8 flavonoides, também sugerimos fingerprints para cada espécie avaliada com base nas substâncias majoritárias, os resultados quantitativos obtidos por UPLC-MS foram eficientes na identificação das espécies com base na filogenia; na terceira, avaliamos as atividades antioxidante, antifúngica e anti-inflamatória de espécies de R... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Despite the several reports of the use of Rhipsalis Gaërtn (Cactaceae) by traditional populations in the treatment of a range of diseases, there are very few phytochemical studies with this group and sometimes these are superficial, only indicating the possible presence of some classes of natural products. In addition, there are very few studies evaluating the biological activity of Rhipsalis. Therefore, this work aimed to investigate the chemical composition of the genus Rhipsalis and to evaluate possible activities related to its composition, thus subsidizing its popular use. This dissertation was divided and organized as follows: the first part presents a general introduction on medicinal plants and their importance as well as a review on phytochemical studies in Cactaceae. Then, three sections were written: in the first one, we investigated the chemical composition of Rhipsalis teres, identifying 5 saponins derived from oleanolic acid, 2 C-glycosilated flavonoids derived from apigenin and 2 phenolic acids; in the second section, we investigate the chemical composition of the genus Rhipsalis identifying 28 saponins whose core is oleanolic acid and 8 flavonoids, we also suggested fingerprints for each species evaluated on the basis of the majority compounds, the quantitative results obtained by UPLC-MS were efficient in the identification of the species based on the phylogeny; in the third, we evaluated the antioxidant, antifungal and anti-inflammatory activities of Rhipsal... (Complete abstract click electronic access below) / Mestre

Les effets de deux types de perturbations anthropiques sévères et ponctuelles (une perturbation physique et une contamination chimique) ont été étudiés sur les propriétés physico-chimiques et biologiques de sols prairiaux. La perturbation physique est engendrée par des travaux de terrassement important pour la création des pistes de ski. L'intensité des travaux conduit à un bouleversement de l'écosystème : la végétation pérenne est arrachée et la nature du sol totalement modifiée. La dégradation chimique est occasionnée par l'épandage d'effluents issus de déchets d'incinération sur une prairie de déprise agricole. Les déchets étudiés sont les mâchefers d'incinération des ordures ménagères (MIOM) et les résidus d'épuration de fumées d'incinération des ordures ménagères (REFIOM). L'évaluation de leur écocompatibilité est basée sur une approche dite en scénarios, c'est à dire de mise en situation des déchets. Nos travaux ont permis de préciser l'influence de la structuration physique du milieu (hétérogénéité physico-chimique et structurale des sols, structure et dynamique de la végétation) sur la réponse des activités et des communautés bactériennes aux perturbations. Les modifications observées dans les profils A-RISA et les profils de restriction des pools de gènes nifH, confirment une implication importante de la structure des sols et de la colonisation des racines, dans l'adaptation et la stratégie démographique des communautés bactériennes globales et fixatrices d'azote. Les modifications environnementales induites par les deux perturbations incitent le développement de communautés bactériennes à stratégie adaptative identique, mais de structure et de composition différentes. Les modifications des activités microbiennes (respiration, fixation d'azote et dénitrification) dévoilent, selon la perturbation, un dysfonctionnement de l'état physiologique de la cellule, de l'expression de l'activité enzymatique ou un déséquilibre dans les populations fonctionnelles. Nos travaux développent et suggèrent l'utilisation d'une démarche intégrant plusieurs échelles d'observation et de multiples indicateurs, pour appréhender la qualité des sols et évaluer l'influence de sa détérioration sur le fonctionnement des écosystèmes terrestres.

<p>Biometrics deals with identifying individuals with help of their biological data. Fingerprint scanning is the most common method of the biometric methods available today. The security of fingerprint scanners has however been questioned and previous studies have shown that fingerprint scanners can be fooled with artificial fingerprints, i.e. copies of real fingerprints. The fingerprint recognition systems are evolving and this study will discuss the situation of today. </p><p>Two approaches have been used to find out how good fingerprint recognition systems are in distinguishing between live fingers and artificial clones. The first approach is a literature study, while the second consists of experiments. </p><p>A literature study of liveness detection in fingerprint recognition systems has been performed. A description of different liveness detection methods is presented and discussed. Methods requiring extra hardware use temperature, pulse, blood pressure, electric resistance, etc., and methods using already existent information in the system use skin deformation, pores, perspiration, etc. </p><p>The experiments focus on making artificial fingerprints in gelatin from a latent fingerprint. Nine different systems were tested at the CeBIT trade fair in Germany and all were deceived. Three other different systems were put up against more extensive tests with three different subjects. All systems werecircumvented with all subjects'artificial fingerprints, but with varying results. The results are analyzed and discussed, partly with help of the A/R value defined in this report.</p>

Computer forensics has become an important technology in providing evidence in investigations of computer misuse, attacks against computer systems and more traditional crimes like money laundering and fraud where digital devices are involved. Investigators frequently perform preliminary analysis at the crime scene on suspects‟ devices to determine the existence of any inappropriate materials such as child pornography on them and conduct further analysis after the seizure of computers to glean leads or valuable evidence. Hence, it is crucial to design a tool which is portable and can perform efficient instant analysis. Many tools have been developed for this purpose, such as Computer Online Forensic Evidence Extractor (COFEE), but unfortunately, they become ineffective in cases where forensic data has been removed. In this thesis, we design a portable forensic tool which can be used to compliment COFEE for preliminary screening to analyze unallocated disk space by adopting a space efficient data structure of fingerprint hash tables for storing the massive forensic data from law enforcement databases in a flash drive and utilizing hash tree indexing for fast searching. We also apply group testing to identify the fragmentation point of the file and locate the starting cluster of each fragment based on statistics on the gap between the fragments. Furthermore, in order to retrieve evidence and clues from unallocated space by recovering deleted files, a file structure based carving algorithm for Windows registry hive files is presented based on their internal structure and unique patterns of storage. / UOIT

This work explores the representations and mathematical modeling of biologically-inspired robotic muscles called Cellular Actuator Arrays. These actuator arrays are made of many small interconnected actuation units which work together to provide force, displacement, robustness and other properties beyond the original actuator's capability. The arrays can also exhibit properties generally associated with biological muscle and can thus provide test bed for research into the interrelated nature of the nervous system and muscles, kinematics/dynamics experiments to understand balance and synergies, and building full-strength, safe muscles for prosthesis, rehabilitation, human force amplification, and humanoid robotics. This thesis focuses on the mathematical tools needed bridge the gap between the conceptual idea of the cellular actuator array and the engineering design processes needed to build physical robotic muscles. The work explores the representation and notation needed to express complex actuator array typologies, the mathematical modeling needed to represent the complex dynamics of the arrays, and properties to guide the selection of arrays for engineering purposes. The approach is designed to aid automation and simulation of actuator arrays and provide an intuitive base for future controls and physiology work. The work is validated through numerical results using MatLab's SimMechanics dynamic modeling system and with three physical actuator arrays built using solenoids and shape memory alloy actuators.

In this study, the soluble protein fraction of P. chrysosporium grown under standard conditions was analyzed by using 2D-PAGE approach and a 2-D reference map was constructed. 910 spots could be separated and detected on Coomassie-stained 2-D gels by the help of Delta2D image analysis software. 720 spots could be cut from the master gel and were subjected to MALDI-TOF MS analysis followed by MASCOT search. A total of 517 spots out of 720 were assigned to specific accession numbers from the P. chrysosporium genome database. Further analysis of the data revealed 314 different gene products (distinct ORFs). The theoretical pI and MW values were plotted against the experimental migration distances. Results indicated the existence of 124 protein spots whose horizontal migration differed significantly from the expected migration according to the calculated pI values and 52 spots with an apparent molecular weight that is significantly different from their theoretical molecular weight. While protein modification could be predicted by these analyses, the main support was the presence of multiple spots of the same gene product. As much as 118 ORFs yielded multiple spots on the master gel, corresponding to 37.5% of the all distinct ORFs identified in this work. The relative abundance of each of the 517 identified polypeptides was calculated in terms of spot intensity. The majority of the most abundant proteins were found to be housekeeping ones. When the relative distribution of the proteins into four main functional categories was taken into consideration, &ldquo / Metabolism&rdquo / appeared the most important category with a share of 50.6% among identified proteins. However, among the functional classes, &ldquo / Posttranslational modifications, protein turnover, chaperones&rdquo / which is listed under the main category &ldquo / Cellular Processing and Signalling&rdquo / was represented by the highest number (104) of the identified proteins. Only 6 of the proteins listed in this study were assigned to hypothetical proteins. Out of the 314 identified gene products shown in P. chrysosporium, 29 were predicted to have a signal peptide sequence according to the SignalP algorithm. By making a WoLF PSORT search, subcellular localization of the proteins was predicted. Accordingly, 147 of the proteins were predicted to be located in cytoplasm. The phosphorylated proteins of P. chrysosporium were detected by ProQ phosphoprotein staining of the 2-D gel. 380 out of 910 distinct protein spots (40%) were found to be phosphorylated in exponentially growing cells of P. chrysosporium. Of these spots, 96 could be matched to the identified proteins.

In der vorliegenden Arbeit wurden 2460 Viertelgemelksproben aus 16 hessischen Milcherzeugerbetrieben untersucht. 115 S. canis-Isolate konnten gefunden und auf ihre morphologischen, biochemischen und bei molekularbiologischen Eigenschaften untersucht werden. Die Isolate stammten von Viertelgemelksproben bzw. Tankproben, die zu einem oder mehreren Zeitpunkten in den Betrieben genommen wurden. Die Untersuchung der biochemischen Eigenschaften erbrachte 24 verschiedene Reaktionsmuster. Der Vergleich dieser 24 Biotypen mit einem S. canis-Referenzstamm mittels tDNA-PCR und 16S-RNA-PCR ergab eine völlige Übereinstimmung (100%) und damit eine sichere Spezies-Identifizierung. Zur Aufklärung epidemiologischer Zusammenhänge und zur Intra-Spezies-Identifizierung wurde von allen 115 Isolaten mittels PFGE nach Makrorestriktionsverdau mit SmaI ein DNA-Fingerprint erstellt. Dabei ergaben sich 21 verschiedene Restriktionsmuster. Von den 21 nach Makrorestriktion mit Sma I und anschließender PFGE unterscheidbaren Restriktionsmustern wurde je ein Isolat zur Bestimmung der Differenzierungsfähigkeit der Restriktionsenzyme Cla I und Apa I sowie der RAPD-PCR weitergehend untersucht. Für die Beurteilung epidemiologischer Zusammenhänge bei S. canis erwies sich die PFGE nach Makrorestriktion mittels Sma I als die differenzierteste Variante. Die mittels PFGE nach Makrorestriktionsverdau mit Sma I durchgeführten Untersuchungen der 115 Isolate zeigten, dass zu einem Probennahme-Termin gewonnene Isolate identisch waren; vom gleichen Betrieb zu unterschiedlichen Zeiten entnommene Proben zeigten z.T. deutliche Unterschiede, und bei Isolaten von verschiedenen Betrieben konnten keine Verwandtschaftsbeziehungen nachgewiesen werden. Aufgrund dieser genotypischen Eigenschaften der Kulturen konnte gezeigt werden, dass es sich bei durch S. canis verursachte Mastitiden um ein infektiöses Bestandsproblem handelt, bei dem der Erreger von Viertel zu Viertel und von Kuh zu Kuh übertragen wird.

Made available in DSpace on 2014-06-11T19:29:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-07-04Bitstream added on 2014-06-13T19:38:57Z : No. of bitstreams: 1 falguera_fps_me_sjrp.pdf: 3832818 bytes, checksum: 1ca4e6b68ff66693475c6e5caed03e88 (MD5) / Biometria refere-se ao uso de características físicas (impressões digitais, íris, retina) ou comportamentais (assinatura, voz) para a identificação humana. As impressões digitais são formadas por cristas e minúcias. As cristas são linhas distribuídas paralelamente com uma orientação e um espaçamento característico e as minúcias representam os vários modos pelos quais uma crista pode se tornar descontínua. Graças a sua universalidade, unicidade e permanência, as impressões digitais tornaram-se as características biométricas mais amplamente utilizadas. Entretanto, considerar o reconhecimento automático de impressões digitais um problema totalmente resolvido é um erro muito comum. Nenhum sistema de reconhecimento de impressões digitais proposto até hoje é infalível, nenhum garante taxas de erro nulas. Imagens de baixa qualidade e com pequena área de sobreposição entre a imagem template e a imagem de consulta ainda representam um desafio para os métodos de reconhecimento de impressões digitais mais utilizados, os métodos baseados no casamento de pontos de minúcias. Uma das maneiras de superar as limitações e melhorar a acurácia de um sistema biométrico é o uso da multibiometria, isto é, a combinação de diferentes tipos de informação em um sistema de reconhecimento biométrico. Neste contexto, esta dissertação de mestrado objetiva aprimorar a acurácia dos sistemas de reconhecimento de impressões digitais por meio da fusão de métodos baseados em minúcias e em cristas. Para tanto, foram implementadas técnicas de fusão no nível de pontuação, classificação e decisão. No nível de pontuação, a fusão propiciou uma redução na taxa de erro igual (EER) de 42,53% em relação ao método mais preciso. Para o nível de classificação, a fusão significou um aumento de 75% na taxa de recuperação correta... / Biometrics refers to the use of physical (fingerprints, iris, retina) or behavioral (signature, voice) characteristics to determine the identity of a person. Fingerprints are formed by ridges and minutiae. The ridges are lines distributed in parallel with an orientation and a characteristic spacing and the minutiae represent the several ways a ridge can become discontinued. As to its universality, uniqueness and permanence, the fingerprints became the most widely used biometric characteristic. However, it is a common mistake to consider the automatic fingerprint recognition as a totally solved problem. No fingerprint recognition system proposed until now is infallible, none of them guarantee null error rates. Poor quality images and when just a small area of overlap between the template and the query images exists are still a complex challenge to the most used fingerprint recognition methods, the methods based on minutiae points matching. One of the possibilities to overcome the limitations and improve the accuracy of a biometric system is the use of multibiometrics, the combination of different kinds of information in a biometric system. In this context, this master thesis aims to improve the accuracy of fingerprint recognition systems through the fusion of minutiae based and ridge based methods. To achieve this, fusion techniques on score, rank and decision levels were implemented. For the score level, the fusion lead to a reduction of the Equal Error Rate to 42.53% compared to the most precise method. For the rank level, the fusion meant an increase of 75% in the Correct Retrieval Rate. And, in the decision level fusion the Recognition Rate changed from 99.25% to 99.75%. The results have demonstrated that the fusion of minutiae based and ridge based methods can represent a significant accuracy improvement for the fingerprint recognition systems.