Machine Learning-based Techniques to Address Spectral Distortions in Photon Counting X-ray Computed Tomography

Spectral CT using a photon counting x-ray detector (PCXD) shows great potential for measuring material composition based on energy dependent x-ray attenuation. Spectral CT is especially suited for imaging with K-edge contrast agents to address the otherwise limited contrast in soft tissues. We have developed a micro-CT system based on a PCXD. This system enables full spectrum CT in which the energy thresholds of the PCXD are swept to sample the full energy spectrum for each detector element and projection angle. Measurements provided by the PCXD, however, are distorted due to undesirable physical eects in the detector and are very noisy due to photon starvation. In this work, we proposed two methods based on machine learning to address the spectral distortion issue and to improve the material decomposition. This rst approach is to model distortions using an articial neural network (ANN) and compensate for the distortion in a statistical reconstruction. The second approach is to directly correct for the distortion in the projections. Both technique can be done as a calibration process where the neural network can be trained using 3D printed phantoms data to learn the distortion model or the correction model of the spectral distortion. This replaces the need for synchrotron measurements required in conventional technique to derive the distortion model parametrically which could be costly and time consuming. The results demonstrate experimental feasibility and potential advantages of ANN-based distortion modeling and correction for more accurate K-edge imaging with a PCXD. Given the computational eciency with which the ANN can be applied to projection data, the proposed scheme can be readily integrated into existing CT reconstruction pipelines.

Adição de Ácido Linoleico conjugado (CLA) no diluidor de congelação de sémen de touro, recolhido Post-Mortem, das raças Holstein Frísia, Aberdeen Angus, Charolês e Limousine

Dissertação de Mestrado, Engenharia Zootécnica, 7 de Abril de 2016, Universidade dos Açores.

Sincronização do estro e coleta de embriões em suínos nacionais

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Agronomia e Medicina Veterinária, 2016.

Contribuciones sobre métodos óptimos y subóptimos de aproximaciones poligonales de curvas 2-D

Esta tesis versa sobre el an álisis de la forma de objetos 2D. En visión articial existen numerosos aspectos de los que se pueden extraer información. Uno de los más usados es la forma o el contorno de esos objetos. Esta característica visual de los objetos nos permite, mediante el procesamiento adecuado, extraer información de los objetos, analizar escenas, etc. No obstante el contorno o silueta de los objetos contiene información redundante. Este exceso de datos que no aporta nuevo conocimiento debe ser eliminado, con el objeto de agilizar el procesamiento posterior o de minimizar el tamaño de la representación de ese contorno, para su almacenamiento o transmisión. Esta reducción de datos debe realizarse sin que se produzca una pérdida de información importante para representación del contorno original. Se puede obtener una versión reducida de un contorno eliminando puntos intermedios y uniendo los puntos restantes mediante segmentos. Esta representación reducida de un contorno se conoce como aproximación poligonal. Estas aproximaciones poligonales de contornos representan, por tanto, una versión comprimida de la información original. El principal uso de las mismas es la reducción del volumen de información necesario para representar el contorno de un objeto. No obstante, en los últimos años estas aproximaciones han sido usadas para el reconocimiento de objetos. Para ello los algoritmos de aproximaci ón poligonal se han usado directamente para la extracci ón de los vectores de caracter ísticas empleados en la fase de aprendizaje. Las contribuciones realizadas por tanto en esta tesis se han centrado en diversos aspectos de las aproximaciones poligonales. En la primera contribución se han mejorado varios algoritmos de aproximaciones poligonales, mediante el uso de una fase de preprocesado que acelera estos algoritmos permitiendo incluso mejorar la calidad de las soluciones en un menor tiempo. En la segunda contribución se ha propuesto un nuevo algoritmo de aproximaciones poligonales que obtiene soluciones optimas en un menor espacio de tiempo que el resto de métodos que aparecen en la literatura. En la tercera contribución se ha propuesto un algoritmo de aproximaciones que es capaz de obtener la solución óptima en pocas iteraciones en la mayor parte de los casos. Por último, se ha propuesto una versi ón mejorada del algoritmo óptimo para obtener aproximaciones poligonales que soluciona otro problema de optimización alternativo.

Exploration of the dendritic cell algorithm with the duration calculus

As one of the newest members in Articial Immune Systems (AIS), the Dendritic Cell Algorithm (DCA) has been applied to a range of problems. These applications mainly belong to the eld of anomaly detection. However, real-time detection, a new challenge to anomaly detection, requires improvement on the real-time capability of the DCA. To assess such capability, formal methods in the research of real-time systems can be employed. The ndings of the assessment can provide guideline for the future development of the algorithm. Therefore, in this paper we use an interval logic based method, named the Duration Calcu- lus (DC), to specify a simplied single-cell model of the DCA. Based on the DC specications with further induction, we nd that each individual cell in the DCA can perform its function as a detector in real-time. Since the DCA can be seen as many such cells operating in parallel, it is potentially capable of performing real-time detection. However, the analysis process of the standard DCA constricts its real-time capability. As a result, we conclude that the analysis process of the standard DCA should be replaced by a real-time analysis component, which can perform periodic analysis for the purpose of real-time detection.

PCA 4 DCA: the application of principal component analysis to the Dendritic Cell Algorithm

As one of the newest members in the field of articial immune systems (AIS), the Dendritic Cell Algorithm (DCA) is based on behavioural models of natural dendritic cells (DCs). Unlike other AIS, the DCA does not rely on training data, instead domain or expert knowledge is required to predetermine the mapping between input signals from a particular instance to the three categories used by the DCA. This data preprocessing phase has received the criticism of having manually over-fitted the data to the algorithm, which is undesirable. Therefore, in this paper we have attempted to ascertain if it is possible to use principal component analysis (PCA) techniques to automatically categorise input data while still generating useful and accurate classication results. The integrated system is tested with a biometrics dataset for the stress recognition of automobile drivers. The experimental results have shown the application of PCA to the DCA for the purpose of automated data preprocessing is successful.

Radio Frequency Superconducting Quantum Interference Device Meta-atoms and Metamaterials: Experiment, Theory, and Analysis

Metamamterials are 1D, 2D or 3D arrays of articial atoms. The articial atoms, called "meta-atoms", can be any component with tailorable electromagnetic properties, such as resonators, LC circuits, nano particles, and so on. By designing the properties of individual meta-atoms and the interaction created by putting them in a lattice, one can create a metamaterial with intriguing properties not found in nature. My Ph. D. work examines the meta-atoms based on radio frequency superconducting quantum interference devices (rf-SQUIDs); their tunability with dc magnetic field, rf magnetic field, and temperature are studied. The rf-SQUIDs are superconducting split ring resonators in which the usual capacitance is supplemented with a Josephson junction, which introduces strong nonlinearity in the rf properties. At relatively low rf magnetic field, a magnetic field tunability of the resonant frequency of up to 80 THz/Gauss by dc magnetic field is observed, and a total frequency tunability of 100% is achieved. The macroscopic quantum superconducting metamaterial also shows manipulative self-induced broadband transparency due to a qualitatively novel nonlinear mechanism that is different from conventional electromagnetically induced transparency (EIT) or its classical analogs. A near complete disappearance of resonant absorption under a range of applied rf flux is observed experimentally and explained theoretically. The transparency comes from the intrinsic bi-stability and can be tuned on/ off easily by altering rf and dc magnetic fields, temperature and history. Hysteretic in situ 100% tunability of transparency paves the way for auto-cloaking metamaterials, intensity dependent filters, and fast-tunable power limiters. An rf-SQUID metamaterial is shown to have qualitatively the same behavior as a single rf-SQUID with regards to dc flux, rf flux and temperature tuning. The two-tone response of self-resonant rf-SQUID meta-atoms and metamaterials is then studied here via intermodulation (IM) measurement over a broad range of tone frequencies and tone powers. A sharp onset followed by a surprising strongly suppressed IM region near the resonance is observed. This behavior can be understood employing methods in nonlinear dynamics; the sharp onset, and the gap of IM, are due to sudden state jumps during a beat of the two-tone sum input signal. The theory predicts that the IM can be manipulated with tone power, center frequency, frequency difference between the two tones, and temperature. This quantitative understanding potentially allows for the design of rf-SQUID metamaterials with either very low or very high IM response.

Dose inseminante para fertilização artificial de ovócitos de dourado

Objetivou-se determinar a dose inseminante adequada para uso na fertilização artificial de ovócitos de dourado (Salminus brasiliensis). Os ovócitos foram distribuídos em delineamento inteiramente casualizado, e fertilizados com uma das relações espermatozoides/ovócito 6,0×10³; 6,0×10(4); 6,0×10(5); 6,0×10(6) ou 3,0×10(7), cada uma com quatro repetições. Considerou-se unidade experimental uma incubadora de volume útil de 2,5 L, contendo 2,0 mL de ovócitos não-hidratados. As taxas de fertilização foram mensuradas 8 horas após o início da fertilização. Com intuito de verificar possíveis efeitos da diluição seminal na movimentação dos espermatozoides, realizou-se a mensuração do tempo de duração da motilidade espermática dos espermatozoides de dourado, ativados por meio de diferentes relações de diluição: 6,8×10-5; 6,8×10-4; 6,8×10-3; 6,8×10-2; 3,4×10-1 e 1,0 mL de sêmen por mL de água. O tempo de duração da motilidade foi avaliado em delineamento inteiramente casualizado composto de seis tratamentos e três repetições. As taxas de fertilização apresentaram relação quadrática com o número de espermatozoides por ovócito. As relações de diluição do sêmen tiveram efeito inversamente proporcional sobre a duração da motilidade espermática. A relação que proporcionou melhores taxas de fertilização artificial de ovócitos de dourado (Salminus brasiliensis) foi de 30.722 espermatozoides por ovócio.

Manual prático para acompanhamento genético em rebanhos comerciais de gado de corte.

O propósito do melhoramento genético e as estratégias para se obter progresso; Touros jovens geneticamente superiores e biotécnicas reprodutivas - por que priorizá-los; Atividades e considerações para o correto acompanhamento e coleta de dados necessários para a avaliação da evolução do rebanho em termos genéticos

Clínica de animais exóticos

Este relatório de estágio descreve as atividades desenvolvidas no estágio curricular e desenvolve o tema ―Inseminação artificial em Python regius‖. O estágio de seis meses foi realizado na Exoclinic – clínica veterinária de aves e exóticos, permitindo consolidar conhecimentos através da prática clínica e agregar-lhes a área da medicina de animais exóticos, dedicando especial atenção à medicina de répteis. Desenvolvem-se os casos mais frequentes: medicina preventiva nas várias classes de animais, patologia dentária em roedores e lagomorfos, doença do bico e das penas dos psitacídeos e anorexia em répteis. Na monografia aborda-se a anatomofisiologia e o comportamento reprodutivos das cobras e a sua influência no maneio reprodutivo em cativeiro, métodos de avaliação de reprodutores e técnicas de inseminação artificial. Realizou-se um ensaio prático com seis animais, realizando colheitas de sémen, avaliação de alguns parâmetros do sémen, controlo folicular por ecografia e inseminação artificial. Apresentam-se os métodos, os resultados e respetiva discussão; Abstract: Exotic animal medicine This traineeship report describes the activities during the traineeship and develops the theme "Artificial insemination in Python regius." The six-month internship was held in Exoclinic - clínica veterinária de aves e exóticos, consolidating knowledge through clinical practice and adding the medical field of exotic animals, with special attention to reptiles. The most frequent clinical cases are developed: preventive medicine in the various classes of animals, dental pathology in rodents and lagomorphs, Psittacine Beak and Feather Disease in birds and anorexia in reptile. The monograph addresses the anatomy, physiology and reproductive behavior of snakes and their influence on reproductive management in captivity, methods for reproductors selection and evaluation and artificial insemination techniques. Implementation of a field trial with six animals, performing semen crops and evaluation of some of its parameters, follicular monitoring by ultrasound and artificial insemination. Methods and results are presented and discussed.

Cirurgia e clínica de espécies pecuárias

Neste relatório são, primeiramente, descritas as atividades desenvolvidas durante o Estágio Curricular do Mestrado Integrado em Medicina Veterinária da Universidade de Évora, no âmbito de clínica e cirurgia de espécies pecuárias. Pretendeu-se, depois, determinar se a suplementação de bovinos de aptidão leiteira com β-caroteno injetável contribui para reduzir o número de inseminações artificiais necessárias para uma gestação. Por outro lado avaliou-se a influência que podem ter algumas variáveis, como sejam a estação do ano ou o número de partos da vaca. Procurou-se, ainda, estudar a evolução dos teores séricos de β-caroteno nos animais suplementados e não suplementados com Dalmafertyl®, utilizando a técnica de cromatografia líquida de alta eficácia ultravioleta. A suplementação parenteral de β-caroteno, nomeadamente com Dalmafertyl®, na Primavera, mostra resultados benéficos na reprodução de vacas e novilhas de aptidão leiteira, aumentando a produtividade e diminuindo custos; ABSTRACT: LARGE ANIMAL SURGERY AND CLINICS On the following report are described the activities that took place during the Curricular Externship as part of the Veterinary Medicine Integrated Masters from University of Évora, in large animal surgery and clinics. Also, it was intended to determine if injectable β-carotene supplementation on dairy cattle can be a decreasing factor on the artificial insemination number needed to result in pregnancy. On the other hand, it was assessed its influence on some variables that can affect pregnancy, such as seasons and calving number. It has been studied the evolution of β-carotene serum levels on Dalmafertyl® supplemented and non-supplemented animals using the high-performance liquid chromatography ultraviolet detection method, as well. β-carotene parenteral supplementation using Dalmafertyl® seems to have benefic results on dairy cattle reproduction when it comes to Spring, which leads to productivity increase and cost decrease

Burrknots as food source for larval development of Grapholita molesta (Lepidoptera: Tortricidae) on apple trees.

Grapholita molesta (Busck) is one of the main pests of apple trees, and lives on their shoots and fruits. In southern Brazil, the insect is also found on old branches and structures similar to aerial roots, so-called burrknots. This study evaluated the development and population growth potential of G. molesta fed on burrknots, compared with apple fruit cultivar. Fuji and a corn-based artiÞcial diet. The study was carried out in the laboratory under controlled temperature (25 1C), relative humidity (7010%), and photophase (16 h). The biological parameters of the immature and adult stages were determined, and a fertility life table was constructed. Insects fed on burrknots showed a longer duration and a lower survival for the egg-to-adult period (29.3 d and 22.5%) compared with those that fed on apples (25.1 d and 30.0%) and artiÞcial diet (23.9 d and 54.8%). Insects reared on aerial roots had a lower pupal weight (10.0 mg) compared with those reared on either artiÞcial diet (13.7 mg) or apple cultivar. Fuji (12.4 mg). The fecundity and longevity of males and females did not signiÞcantly differ for the three foods. Based on the fertility life table, insects reared on burrknots had the lowest net reproductive rate (Ro), intrinsic rate of population growth (rm) and finite rate of increase, compared with insects reared on artiÞcial diet and apple fruit. Burrknots support the development of the complete cycle of G. molesta, which allows populations of this pest to increase in orchards.