Boundary Peeling: Outlier Detection Method Using One-Class Peeling

Unsupervised outlier detection constitutes a crucial phase within data analysis and remains a dynamic realm of research. A good outlier detection algorithm should be computationally efficient, robust to tuning parameter selection, and perform consistently well across diverse underlying data distributions. We introduce One-Class Boundary Peeling, an unsupervised outlier detection algorithm. One-class Boundary Peeling uses the average signed distance from iteratively-peeled, flexible boundaries generated by one-class support vector machines. One-class Boundary Peeling has robust hyperparameter settings and, for increased flexibility, can be cast as an ensemble method. In synthetic data simulations One-Class Boundary Peeling outperforms all state of the art methods when no outliers are present while maintaining comparable or superior performance in the presence of outliers, as compared to benchmark methods. One-Class Boundary Peeling performs competitively in terms of correct classification, AUC, and processing time using common benchmark data sets

Optimal Supersaturated Designs for Lasso Sign Recovery

Supersaturated designs, in which the number of factors exceeds the number of runs, are often constructed under a heuristic criterion that measures a design's proximity to an unattainable orthogonal design. Such a criterion does not directly measure a design's quality in terms of screening. To address this disconnect, we develop optimality criteria to maximize the lasso's sign recovery probability. The criteria have varying amounts of prior knowledge about the model's parameters. We show that an orthogonal design is an ideal structure when the signs of the active factors are unknown. When the signs are assumed known, we show that a design whose columns exhibit small, positive correlations are ideal. Such designs are sought after by the Var(s+)-criterion. These conclusions are based on a continuous optimization framework, which rigorously justifies the use of established heuristic criteria. From this justification, we propose a computationally-efficient design search algorithm that filters through optimal designs under different heuristic criteria to select the one that maximizes the sign recovery probability under the lasso

Transmission of MRSA between Companion Animals and Infected Human Patients Presenting to Outpatient Medical Care Facilities

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen in both human and veterinary medicine. The importance of companion animals as reservoirs of human infections is currently unknown. The companion animals of 49 MRSA-infected outpatients (cases) were screened for MRSA carriage, and their bacterial isolates were compared with those of the infected patients using Pulsed-Field Gel Electrophoresis (PFGE). Rates of MRSA among the companion animals of MRSA-infected patients were compared to rates of MRSA among companion animals of pet guardians attending a “veterinary wellness clinic” (controls). MRSA was isolated from at least one companion animal in 4/49 (8.2%) households of MRSA-infected outpatients vs. none of the pets of the 50 uninfected human controls. Using PFGE, patient-pets MRSA isolates were identical for three pairs and discordant for one pair (suggested MRSA inter-specie transmission p-value = 0.1175). These results suggest that companion animals of MRSA-infected patients can be culture-positive for MRSA, representing a potential source of infection or re-infection for humans. Further studies are required to better understand the epidemiology of MRSA human-animal inter-specie transmission

Antibacterial Characterization of Novel Synthetic Thiazole Compounds against Methicillin-Resistant Staphylococcus pseudintermedius

Staphylococcus pseudintermedius is a commensal organism of companion animals that is a significant source of opportunistic infections in dogs. With the emergence of clinical isolates of S. pseudintermedius (chiefly methicillin-resistant S. pseudintermedius (MRSP)) exhibiting increased resistance to nearly all antibiotic classes, new antimicrobials and therapeutic strategies are urgently needed. Thiazole compounds have been previously shown to possess potent antibacterial activity against multidrug-resistant strains of Staphylococcus aureus of human and animal concern. Given the genetic similarity between S. aureus and S. pseudintermedius, this study explores the potential use of thiazole compounds as novel antibacterial agents against methicillin-sensitive S. pseudintermedius (MSSP) and MRSP. A broth microdilution assay confirmed these compounds exhibit potent bactericidal activity (at sub-microgram/mL concentrations) against both MSSA and MRSP clinical isolates while the MTS assay confirmed three compounds (at 10 μg/mL) were not toxic to mammalian cells. A time-kill assay revealed two derivatives rapidly kill MRSP within two hours. However, this rapid bactericidal activity was not due to disruption of the bacterial cell membrane indicating an alternative mechanism of action for these compounds against MRSP. A multistep resistance selection analysis revealed compounds 4 and 5 exhibited a modest (twofold) shift in activity over ten passages. Furthermore, all six compounds (at a subinihibitory concentration) demonstrated the ability to re-sensitize MRSP to oxacillin, indicating these compounds have potential use for extending the therapeutic utility of β-lactam antibiotics against MRSP. Metabolic stability analysis with dog liver microsomes revealed compound 3 exhibited an improved physicochemical profile compared to the lead compound. In addition to this, all six thiazole compounds possessed a long post-antibiotic effect (at least 8 hours) against MRSP. Collectively the present study demonstrates these synthetic thiazole compounds possess potent antibacterial activity against both MSSP and MRSP and warrant further investigation into their use as novel antimicrobial agents

XCAT-GAN for Synthesizing 3D Consistent Labeled Cardiac MR Images on Anatomically Variable XCAT Phantoms

Generative adversarial networks (GANs) have provided promising data enrichment solutions by synthesizing high-fidelity images. However, generating large sets of labeled images with new anatomical variations remains unexplored. We propose a novel method for synthesizing cardiac magnetic resonance (CMR) images on a population of virtual subjects with a large anatomical variation, introduced using the 4D eXtended Cardiac and Torso (XCAT) computerized human phantom. We investigate two conditional image synthesis approaches grounded on a semantically-consistent mask-guided image generation technique: 4-class and 8-class XCAT-GANs. The 4-class technique relies on only the annotations of the heart; while the 8-class technique employs a predicted multi-tissue label map of the heart-surrounding organs and provides better guidance for our conditional image synthesis. For both techniques, we train our conditional XCAT-GAN with real images paired with corresponding labels and subsequently at the inference time, we substitute the labels with the XCAT derived ones. Therefore, the trained network accurately transfers the tissue-specific textures to the new label maps. By creating 33 virtual subjects of synthetic CMR images at the end-diastolic and end-systolic phases, we evaluate the usefulness of such data in the downstream cardiac cavity segmentation task under different augmentation strategies. Results demonstrate that even with only 20% of real images (40 volumes) seen during training, segmentation performance is retained with the addition of synthetic CMR images. Moreover, the improvement in utilizing synthetic images for augmenting the real data is evident through the reduction of Hausdorff distance up to 28% and an increase in the Dice score up to 5%, indicating a higher similarity to the ground truth in all dimensions

Alimentação natural para cães e gatos Natural foods for dogs and cats

Um grande "recall" de alimentos PET ocorrido em 2007 nos Estados Unidos devido à contaminação fraudulenta por melamina, foi ponto chave para o interesse atual sobre novas alternativas alimentares para cães e gatos, a parte a rações comerciais convencionais. A procura por novidades no setor pet food, combinada com uma tendência permanente de humanização na indústria pet, acarreta aumento da procura por alimentos diferenciados para animais de estimação. Dentre os tipos de dietas alternativas encontram-se as dietas naturais, as orgânicas, entre outras. Entretanto, não existem orientações específicas para a fabricação e rotulagem de produtos que contenham carne crua, o que poderia ocasionar desequilíbrios e risco à saúde de proprietários que fornecem esse tipo de alimentação a seus animais de estimação. Por outro lado, os alimentos naturais podem ser constituídos por ingredientes destinados à alimentação humana, buscando uma aproximação da composição dos alimentos que os animais (cães e gatos) obtinham da natureza, com maior contribuição dos nutrientes, como proteína e lipídeos, a esses animais. Os efeitos que estes podem causar em animais de estimação são diversos, desde parâmetros relacionados ao surgimento de doenças, por afetarem o metabolismo de proteínas, carboidratos e/ou lipídeos, até fatores ligados à qualidade fecal e, mais além, na questão da segurança alimentar. Assim, os alimentos comerciais naturais são nichos de mercado potenciais e surgiram para atender a demanda de proprietários cada vez mais exigentes com relação à alimentação e nutrição de seus animais de companhia. Entretanto, é importante uma avaliação criteriosa e científica deste nicho de mercado, buscando estabelecer suas vantagens e desvantagens sob o ponto de vista nutricional e de segurança alimentar.<br>A major pet food recall occurred in 2007 in the United States due to fraudulent contamination with melamine was key to the current interest on new food alternatives for dogs and cats, the party to conventional commercial ration. The demand for exclusivity in the pet food industry, combined with a permanent trend of humanization in pet industry, increased the demand for differentiated food for pets. Among the types of alternative diets are called natural foods and organic, among others. However, no specific guidance on the approach to manufacturing and labeling of products containing raw meat, which could cause instability and risk the health of owners that by provide that type of food to their pets. Moreover, natural foods can be made of ingredients for food, seeking an approximation of the composition of the foods that animals (dogs and cats) obtained from nature, with higher contribution of nutrients such as proteins and lipids in these animals. The effects they may cause in pets are different from parameters related to the emergence of diseases that affect the metabolism of proteins, carbohydrates and / or lipid factors related to the quality fecal and beyond, the question of safety food. Thus, the commercial foods are natural and potential market niches have emerged to meet the demand of owners increasingly demanding in relation to food and nutrition for their pets. However, it is important to a thorough and scientific assessment of this niche market, seeking to establish its upside and downside from the point of view of nutrition and food security