501 research outputs found

    Evolution: A View from the 21st Century

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    Modeling and Analysis of Power Processing Systems (MAPPS). Volume 2: Appendices

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    The computer programs and derivations generated in support of the modeling and design optimization program are presented. Programs for the buck regulator, boost regulator, and buck-boost regulator are described. The computer program for the design optimization calculations is presented. Constraints for the boost and buck-boost converter were derived. Derivations of state-space equations and transfer functions are presented. Computer lists for the converters are presented, and the input parameters justified

    A novel method for detecting optimal location and parameters of power system stabilizer (PSS) based on intelligent techniques

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    ABSTRACT: This paper presents a new technique to design a Power System Stabilizer (PSS) in multi-machine power system. The method is based on the Particle Swarm Optimization (PSO) algorithm for tuning PSS parameters including lead-lag compensator time constants as well as the controller gain. For evaluating the particles evolution throughout the searching process, an eigenvalue-based multi-objective function is used. The DIgSILENT is used as tool for modelling test system and programming PSO algorithm. Then by using a fuzzy approach implemented in Matlab/fuzzy toolbox the optimal number and location for PSSs specified. Two-area (four-machine 11bus) Power system is considered as the case study in this paper. Simulation results for various operating conditions prove the capability of the proposed algorithm in damping improvement of power system

    Note on the occurrence of parasites of the wild nutria (Myocastor coypus, Molina, 1782)

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    Summary: We examined the endoparasites of wild nutria from the native region of South America. Individuals were infected with nineteen species, including Nematoda (82. 0 %), Protozoa (46. 1 %), Trematoda (33. 3 %) and Cestoda (12. 8%). Coccidia (Eimeria sp. or Isospora sp.), Strongyloides myopotami and Trichuris myocastoris were the most abundant and prevalent parasites. The diversity of parasite collected on individual hosts ranged from one to four species. There was no significant association between either the age or the sex of the nutria and the prevalence of parasitism, except that the number of infested nutria less than 1 year by Nematoda was significantly higher than in older individuals. Additionally, Cryptosporidium spp. and Giardia spp. were demonstrated in fecal samples, although scarcely. In general, the accessions were found in good bodily condition and carrying low parasite burdens. These numbers appeared insufficient to indicate gastrointestinal parasitism or parasitic disease.Facultad de Ciencias Veterinaria

    Note on the occurrence of parasites of the wild nutria (Myocastor coypus, Molina, 1782)

    Get PDF
    Summary: We examined the endoparasites of wild nutria from the native region of South America. Individuals were infected with nineteen species, including Nematoda (82. 0 %), Protozoa (46. 1 %), Trematoda (33. 3 %) and Cestoda (12. 8%). Coccidia (Eimeria sp. or Isospora sp.), Strongyloides myopotami and Trichuris myocastoris were the most abundant and prevalent parasites. The diversity of parasite collected on individual hosts ranged from one to four species. There was no significant association between either the age or the sex of the nutria and the prevalence of parasitism, except that the number of infested nutria less than 1 year by Nematoda was significantly higher than in older individuals. Additionally, Cryptosporidium spp. and Giardia spp. were demonstrated in fecal samples, although scarcely. In general, the accessions were found in good bodily condition and carrying low parasite burdens. These numbers appeared insufficient to indicate gastrointestinal parasitism or parasitic disease.Facultad de Ciencias Veterinaria

    Pulmonary interstitial glycogenosis: an unrecognized etiology of persistent pulmonary hypertension of the newborn in congenital heart disease?

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    BACKGROUND: Pulmonary interstitial glycogenosis (PIG) arises from a developmental disorder of the pulmonary mesenchyme and presents clinically with reversible neonatal respiratory distress and/or persistent pulmonary hypertension of the newborn (PPHN). OBJECTIVE: We report two cases of PIG in patients with congenital heart disease (CHD) and evidence of PPHN. RESULTS: Both cases demonstrated the hallmark PIG histologic finding of diffuse, uniform interstitial thickening due to the presence of immature interstitial cells containing abundant cytoplasmic glycogen. CONCLUSIONS: We report the second and third patients with PIG associated with CHD. Because histologic examination is required to establish the diagnosis, we speculate that PIG, although rare, may be underrecognized in neonates presenting with PPHN in the setting of CHD

    Quantitative test of the barrier nucleosome model for statistical positioning of nucleosomes up- and downstream of transcription start sites

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    The positions of nucleosomes in eukaryotic genomes determine which parts of the DNA sequence are readily accessible for regulatory proteins and which are not. Genome-wide maps of nucleosome positions have revealed a salient pattern around transcription start sites, involving a nucleosome-free region (NFR) flanked by a pronounced periodic pattern in the average nucleosome density. While the periodic pattern clearly reflects well-positioned nucleosomes, the positioning mechanism is less clear. A recent experimental study by Mavrich et al. argued that the pattern observed in S. cerevisiae is qualitatively consistent with a `barrier nucleosome model', in which the oscillatory pattern is created by the statistical positioning mechanism of Kornberg and Stryer. On the other hand, there is clear evidence for intrinsic sequence preferences of nucleosomes, and it is unclear to what extent these sequence preferences affect the observed pattern. To test the barrier nucleosome model, we quantitatively analyze yeast nucleosome positioning data both up- and downstream from NFRs. Our analysis is based on the Tonks model of statistical physics which quantifies the interplay between the excluded-volume interaction of nucleosomes and their positional entropy. We find that although the typical patterns on the two sides of the NFR are different, they are both quantitatively described by the same physical model, with the same parameters, but different boundary conditions. The inferred boundary conditions suggest that the first nucleosome downstream from the NFR (the +1 nucleosome) is typically directly positioned while the first nucleosome upstream is statistically positioned via a nucleosome-repelling DNA region. These boundary conditions, which can be locally encoded into the genome sequence, significantly shape the statistical distribution of nucleosomes over a range of up to ~1000 bp to each side.Comment: includes supporting materia

    A hybrid method for accurate iris segmentation on at-a-distance visible-wavelength images

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    [EN] This work describes a new hybrid method for accurate iris segmentation from full-face images independently of the ethnicity of the subject. It is based on a combination of three methods: facial key-point detection, integro-differential operator (IDO) and mathematical morphology. First, facial landmarks are extracted by means of the Chehra algorithm in order to obtain the eye location. Then, the IDO is applied to the extracted sub-image containing only the eye in order to locate the iris. Once the iris is located, a series of mathematical morphological operations is performed in order to accurately segment it. Results are obtained and compared among four different ethnicities (Asian, Black, Latino and White) as well as with two other iris segmentation algorithms. In addition, robustness against rotation, blurring and noise is also assessed. Our method obtains state-of-the-art performance and shows itself robust with small amounts of blur, noise and/or rotation. Furthermore, it is fast, accurate, and its code is publicly available.Fuentes-Hurtado, FJ.; Naranjo Ornedo, V.; Diego-Mas, JA.; Alcañiz Raya, ML. (2019). A hybrid method for accurate iris segmentation on at-a-distance visible-wavelength images. EURASIP Journal on Image and Video Processing (Online). 2019(1):1-14. https://doi.org/10.1186/s13640-019-0473-0S11420191A. Radman, K. Jumari, N. Zainal, Fast and reliable iris segmentation algorithm. IET Image Process.7(1), 42–49 (2013).M. Erbilek, M. Fairhurst, M. C. D. C Abreu, in 5th International Conference on Imaging for Crime Detection and Prevention (ICDP 2013). Age prediction from iris biometrics (London, 2013), pp. 1–5. http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6913712&isnumber=6867223 .A. Abbasi, M. Khan, Iris-pupil thickness based method for determining age group of a person. Int. Arab J. Inf. Technol. (IAJIT). 13(6) (2016).G. Mabuza-Hocquet, F. Nelwamondo, T. 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Wildes, Iris recognition: an emerging biometric technology. Proc. IEEE. 85(9), 1348–1363 (1997).M. Kass, A. Witkin, D. Terzopoulos, Snakes: Active contour models. Int. J. Comput. Vision. 1(4), 321–331 (1988).S. J. Pundlik, D. L. Woodard, S. T. Birchfield, in 2008 IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops. Non-ideal iris segmentation using graph cuts (IEEEAnchorage, 2008). p. 1–6. http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4563108&isnumber=4562948 .H. Proença, Iris recognition: On the segmentation of degraded images acquired in the visible wavelength. IEEE Trans. Pattern Anal. Mach. Intell.32(8), 1502–1516 (2010). http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5156505&isnumber=5487331 .T. Tan, Z. He, Z. Sun, Efficient and robust segmentation of noisy iris images for non-cooperative iris recognition. Image Vision Comput.28(2), 223–230 (2010).C. -W. Tan, A. Kumar, in CVPR 2011 WORKSHOPS. 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Image Vision Comput. 28(2), 261–269 (2010).Z. Zhao, A. Kumar, in 2015 IEEE International Conference on Computer Vision (ICCV). An accurate iris segmentation framework under relaxed imaging constraints using total variation model (Santiago, 2015). p. 3828–3836. http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7410793&isnumber=7410356 .Y. Hu, K. Sirlantzis, G. Howells, Improving colour iris segmentation using a model selection technique. Pattern Recogn. Lett.57:, 24–32 (2015).E. Ouabida, A. Essadique, A. Bouzid, Vander lugt correlator based active contours for iris segmentation and tracking. Expert Systems Appl.71:, 383–395 (2017).C. -W. Tan, A. Kumar, Unified framework for automated iris segmentation using distantly acquired face images. IEEE Trans. Image Proc.21(9), 4068–4079 (2012).C. -W. Tan, A. Kumar, in Proceedings of the 21st International Conference on Pattern Recognition (ICPR2012). 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    Note on the occurrence of parasites of the wild nutria (Myocastor coypus, Molina, 1782)

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    Summary: We examined the endoparasites of wild nutria from the native region of South America. Individuals were infected with nineteen species, including Nematoda (82. 0 %), Protozoa (46. 1 %), Trematoda (33. 3 %) and Cestoda (12. 8%). Coccidia (Eimeria sp. or Isospora sp.), Strongyloides myopotami and Trichuris myocastoris were the most abundant and prevalent parasites. The diversity of parasite collected on individual hosts ranged from one to four species. There was no significant association between either the age or the sex of the nutria and the prevalence of parasitism, except that the number of infested nutria less than 1 year by Nematoda was significantly higher than in older individuals. Additionally, Cryptosporidium spp. and Giardia spp. were demonstrated in fecal samples, although scarcely. In general, the accessions were found in good bodily condition and carrying low parasite burdens. These numbers appeared insufficient to indicate gastrointestinal parasitism or parasitic disease.Facultad de Ciencias Veterinaria
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