4,633 research outputs found

    Innovative molecular diagnosis of Trichinella species based on β-carbonic anhydrase genomic sequence

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    Trichinellosis is a helminthic infection where different species of Trichinella nematodes are the causative agents. Several molecular assays have been designed to aid diagnostics of trichinellosis. These assays are mostly complex and expensive. The genomes of Trichinella species contain certain parasite-specific genes, which can be detected by polymerase chain reaction (PCR) methods. We selected -carbonic anhydrase (-CA) gene as a target, because it is present in many parasites genomes but absent in vertebrates. We developed a novel -CA gene-based method for detection of Trichinella larvae in biological samples. We first identified a -CA protein sequence from Trichinella spiralis by bioinformatic tools using -CAs from Caenorhabditis elegans and Drosophila melanogaster. Thereafter, 16 sets of designed primers were tested to detect -CA genomic sequences from three species of Trichinella, including T.spiralis, Trichinellapseudospiralis and Trichinellanativa. Among all 16 sets of designed primers, the primer set No. 2 efficiently amplified -CA genomic sequences from T.spiralis, T.pseudospiralis and T.nativa without any false-positive amplicons from other parasite samples including Toxoplasma gondii, Toxocara cati and Parascaris equorum. This robust and straightforward method could be useful for meat inspection in slaughterhouses, quality control by food authorities and medical laboratories.Peer reviewe

    Tversky loss function for image segmentation using 3D fully convolutional deep networks

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    Fully convolutional deep neural networks carry out excellent potential for fast and accurate image segmentation. One of the main challenges in training these networks is data imbalance, which is particularly problematic in medical imaging applications such as lesion segmentation where the number of lesion voxels is often much lower than the number of non-lesion voxels. Training with unbalanced data can lead to predictions that are severely biased towards high precision but low recall (sensitivity), which is undesired especially in medical applications where false negatives are much less tolerable than false positives. Several methods have been proposed to deal with this problem including balanced sampling, two step training, sample re-weighting, and similarity loss functions. In this paper, we propose a generalized loss function based on the Tversky index to address the issue of data imbalance and achieve much better trade-off between precision and recall in training 3D fully convolutional deep neural networks. Experimental results in multiple sclerosis lesion segmentation on magnetic resonance images show improved F2 score, Dice coefficient, and the area under the precision-recall curve in test data. Based on these results we suggest Tversky loss function as a generalized framework to effectively train deep neural networks

    NMR Evidence for Antiferromagnetic Transition in the Single-Component Molecular Conductor, [Au(tmdt)_{2}] at 110 K

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    We present the results of a ^{1}H NMR study of the single-component molecular conductor, [Au(tmdt)_{2}]. A steep increase in the NMR line width and a peak formation of the nuclear spin-lattice relaxation rate, 1/T_{1}, were observed at around 110 K. This behavior provides clear and microscopic evidences for a magnetic phase transition at considerably high temperature among organic conductors. The observed variation in 1/T_{1} with respect to temperature indicates the highly correlated nature of the metallic phase.Comment: 5pages, 6figures to be published in J. Phys. Soc. Jp

    Using neuroevolution for predicting mobile marketing conversion

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    This paper addresses user Conversion Rate (CVR) prediction within the context of Mobile Performance Marketing. Specifically, we adapt two main neuroevolution methods: Neuroevolution of Augmenting Topologies (NEAT) and Hypercube-based NEAT (HyperNEAT). First, we discuss two mechanisms for increasing execution speed (parallelism and data sampling); a strategy for preventing excessive network complexity with NEAT; and a rolling window scheme for performing an online learning. Then, we present experimental results, using distinct datasets and testing both offline and online learning environments.ThisarticleisaresultoftheprojectNORTE-01-0247-FEDER-017497,supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work was also supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019

    Singlet Stripe Phases in the planar t-J Model

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    The energies of singlet stripe phases in which a plane is broken up into spin liquid ladders by lines of holes, is examined. If the holes were static then patterns containing spin liquids with a finite spin gap are favored. The case of dynamic holes is treated by assembling t-J ladders oriented perpendicular to the stripes. For a wide region around J/t≈1J/t \approx 1 the hole-hole correlations in a single ladder are found to be predominantly charge density wave type but an attraction between hole pairs on adjacent ladders leads to a stripe phase. A quantum mechanical melting of the hole lines at smaller J/tJ/t values leads to a Bose condensate of hole pairs, i.e. a superconducting phase.Comment: 5 pages, uuencoded compressed PostScript file including 5 figures, ETH-TH/942

    Electronic Structure of Stripes in Two-Dimensional Hubbard Model

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    Focusing on La_{2-x}Sr_{x}CuO_{4}, we study the stripe structure by the self-consistent mean-field theory of the Hubbard model. By introducing the realistic Fermi surface topology, the SDW-gapped insulator is changed to metallic. The solitonic features of the stripe structure and the contribution of the mid-gap states are presented. We consider the band dispersion, the local density of states, the spectral weight, and the optical conductivity, associated with the solitonic structure. These results may provide important information for the experimental research of the stripe structure, such as the angle-resolved photoemission experiments. The ``Fermi surface'' shape is changed depending on the ratio of the incommensurability delta and the hole density n_h. In real space, only the stripe region is metallic when delta/n_h is large.Comment: LaTeX 12 pages (using jpsj macros) with 16 figure

    Spin and charge excitations in incommensurate spin density waves

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    Collective excitations both for spin- and charge-channels are investigated in incommensurate spin density wave (or stripe) states on two-dimensional Hubbard model. By random phase approximation, the dynamical susceptibility \chi(q,\omega) is calculated for full range of (q,\omega) with including all higher harmonics components. An intricate landscape of the spectra in \chi(q,\omega) is obtained. We discuss the anisotropy of the dispersion cones for spin wave excitations, and for the phason excitation related to the motion of the stripe line. Inelastic neutron experiments on Cr and its alloys and stripe states of underdoped cuprates are proposed

    Magnetic phase diagram of cubic perovskites SrMn_1-xFe_xO_3

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    We combine the results of magnetic and transport measurements with Mossbauer spectroscopy and room-temperature diffraction data to construct the magnetic phase diagram of the new family of cubic perovskite manganites SrMn_1-xFe_xO_3. We have found antiferromagnetic ordering for lightly and heavily Fe-substituted material, while intermediate substitution leads to spin-glass behavior. Near the SrMn_0.5Fe_0.5O_3 composition these two types of ordering are found to coexist and affect one another. The spin glass behavior may be caused by competing ferro- and antiferromagnetic interactions among Mn^4+ and observed Fe^3+ and Fe^5+ ions.Comment: 8 pages, 10 figures, revtex, accepted to Phys. Rev.

    Searching for the Slater Transition in the Pyrochlore Cd2_{2}Os2_{2}O7_{7} with Infrared Spectroscopy

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    Infrared reflectance measurements were made on the single crystal pyrochlore Cd2_{2}Os2_{2}O7_{7} in order to examine the transformations of the electronic structure and crystal lattice across the boundary of the metal insulator transition at TMIT=226KT_{MIT}=226K. All predicted IR active phonons are observed in the conductivity over all temperatures and the oscillator strength is found to be temperature independent. These results indicate that charge ordering plays only a minor role in the MIT and that the transition is strictly electronic in nature. The conductivity shows the clear opening of a gap with 2Δ=5.2kBTMIT2\Delta=5.2k_{B}T_{MIT}. The gap opens continuously, with a temperature dependence similar to that of BCS superconductors, and the gap edge having a distinct σ(ω)∼ω1/2\sigma(\omega)\thicksim\omega^{1/2} dependence. All of these observables support the suggestion of a Slater transition in Cd2_{2}% Os2_{2}O7_{7}.Comment: 4 pages, 4 figure
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