6,231 research outputs found

    Deep Multi-instance Networks with Sparse Label Assignment for Whole Mammogram Classification

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    Mammogram classification is directly related to computer-aided diagnosis of breast cancer. Traditional methods rely on regions of interest (ROIs) which require great efforts to annotate. Inspired by the success of using deep convolutional features for natural image analysis and multi-instance learning (MIL) for labeling a set of instances/patches, we propose end-to-end trained deep multi-instance networks for mass classification based on whole mammogram without the aforementioned ROIs. We explore three different schemes to construct deep multi-instance networks for whole mammogram classification. Experimental results on the INbreast dataset demonstrate the robustness of proposed networks compared to previous work using segmentation and detection annotations.Comment: MICCAI 2017 Camera Read

    Effects of epitaxial strain on the growth mechanism of YBa2Cu3O7-x thin films in [YBa2Cu3O7-x / PrBa2Cu3O7-x] superlattices

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    We report on the growth mechanism of YBa2Cu3O7-x (YBCO). Our study is based on the analysis of ultrathin, YBa2Cu3O7-x layers in c-axis oriented YBa2Cu3O7-x / PrBa2Cu3O7-x superlattices. We have found that the release of epitaxial strain in very thin YBCO layers triggers a change in the dimensionality of the growth mode. Ultrathin, epitaxially strained, YBCO layers with thickness below 3 unit cells grow in a block by block two dimensional mode coherent over large lateral distances. Meanwhile, when thickness increases, and the strain relaxes, layer growth turns into three dimensional, resulting in rougher layers and interfaces.Comment: 10 pages + 9 figures, accepted in Phys. Rev.

    Limited Depressive and Anxiety Symptoms Late in Pregnancy Are Not Related to Neonatal Outcomes

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    Background: Prior studies have reported inconsistent findings regarding the link between antenatal depressive and anxiety symptomatology, with neonatal outcomes. Objectives: The aim of the present study was to assess the possible association of prenatal depressive and anxiety symptoms, in the third trimester of pregnancy, with perinatal outcomes (birth weight of the newborn, Apgar score and the newborn’s admission in neonatal intensive care unit) in a sample of pregnant women, in Greece. Patients and Methods: A total of 117 women from Athens, during the 32nd to 35th week of pregnancy, participated in the study. Demographic and obstetric history data, as well as neonatal outcomes, were recorded. Three self-administered psychometric scales (Beck depression inventory (BDI), Edinburg postnatal depression scale (EPDS) and beck anxiety inventory (BAI)) were used to evaluate in detail the prenatal depressive and anxiety symptoms. Descriptive statistics, Spearman’s Rho coefficients, Mann-Whitney U and Kruskal-Wallis testes were applied to analyze the data. Results: On the basis of BDI, 81.1% of the sample showed minimal, 15.4% mild, 2.6% moderate and 0.9% severe depressive symptoms, respectively. Furthermore, 80.3% of the participants, scored on EPDS below the cut-off point for a likely diagnosis of depression. According to BAI scale, 43.6% showed minimal, 42.7% women mild, 10.3% moderate and 3.4% severe anxiety symptoms. No statistically significant correlations were found between depressive and anxiety symptoms and neonatal outcomes (birth weight, Apgar score and admission in neonatal intensive care unit). Conclusions: Limited levels of prenatal depressive and anxiety symptoms do not seem to be associated with neonatal outcomes. In clinical practice, pregnant women, who suffer from low levels of prenatal depressive and anxiety symptoms, may be reassured, in respect of the adverse outcomes of these mood symptoms on the neonate

    Anomalous near-field heat transfer between a cylinder and a perforated surface

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    We predict that the radiative heat-transfer rate between a cylinder and a perforated surface depends non-monotonically on their separation. This anomalous behavior, which arises due to near-field effects, is explained using a heuristic model based on the interaction of a dipole with a plate. We show that nonmonotonicity depends not only on geometry and temperature but also on material dispersion - for micron and submicron objects, nonmonotonicity is present in polar dielectrics but absent in metals with small skin depths

    Tempera: spatial transformer feature pyramid network for cardiac MRI segmentation

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    Assessing the structure and function of the right ventricle (RV) is important in the diagnosis of several cardiac pathologies. However, it remains more challenging to segment the RV than the left ventricle (LV). In this paper, we focus on segmenting the RV in both short (SA) and long-axis (LA) cardiac MR images simultaneously. For this task, we propose a new multi-input/output architecture, hybrid 2D/3D geometric spatial TransformEr Multi-Pass fEature pyRAmid (Tempera). Our feature pyramid extends current designs by allowing not only a multi-scale feature output but multi-scale SA and LA input images as well. Tempera transfers learned features between SA and LA images via layer weight sharing and incorporates a geometric target transformer to map the predicted SA segmentation to LA space. Our model achieves an average Dice score of 0.836 and 0.798 for the SA and LA, respectively, and 26.31 mm and 31.19 mm Hausdorff distances. This opens up the potential for the incorporation of RV segmentation models into clinical workflows

    The nanostructural origin of the ac conductance in dielectric granular metals: the case study of Co_20(ZrO_2)_80

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    We show which is the nanostructure required in granular Co20(ZrO2)80 thin films to produce an ac response such as the one that is universally observed in a very wide variety of dielectric materials. A bimodal size distribution of Co particles yields randomly competing conductance channels which allow both thermally assisted tunneling through small particles and capacitive conductance among larger particles that are further apart. A model consisting on a simple cubic random resistance-capacitor network describes quantitatively the experimental results as functions of temperature and frequency, and enables the determination of the microscopic parameters controlling the ac response of the samples.Comment: Available online at: http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000091000005052108000001&idtype=cvips&gifs=ye

    Suitability of aquatic mosses for biomonitoring micro/meso plastics in freshwater ecosystems

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    Abstract Background Mesoplastics (5–25 mm) and microplastics (0.001–5 mm) are emerging pollutants of great concern. However, reliable methods of monitoring these types of plastic in river ecosystems have not yet been established. The goal of this work was to evaluate, for the first time, the suitability of Fontinalis antipyretica as a biomonitor of meso- and micro-plastics in rivers. With this aim, native samples of the moss and devitalized moss clones, held inside the bags, were compared for the uptake of fluorescent polystyrene particles under laboratory conditions, and for retention of plastic debris in the field, in sites close to wastewater treatment plants. Results In the laboratory experiment, the moss retained smaller microplastics, and a higher number of polystyrene meso and microplastics was counted in the moss bags than in the native moss. In the field study, the moss retained plastic debris chiefly in the form of fibres regardless of the capacity and flow rate of the wastewater treatment plants affecting each sampling site. The uniform morphology of moss clone seems to affect the retention of this type of pollutant. The FTIR analysis confirmed the particles entrapped by the moss bags as plastic, specifically polyethylene and polyamide type 6, among the most common plastic polymers detected in rivers. Conclusions The study findings highlighted the value of using uniform material, as the clone exhibited a greater accumulation efficiency with respect to the native moss. The mesh bags could act as selective filters and/or prevent the loss of adhering plastics. In the field, the bags favour plastic fibres retention despite the river flow. Finally, although FTIR is useful for the identification of plastic type, it is not very sensitive when small quantities of ground samples are used

    Influence of Oil Prices in Dynamic Positioning Training

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    The main purpose of this research is to present the influence of the oil price drop in the offshore training industry and the actions taken to minimise this effect. In particular, data corresponding to the Offshore Dynamic Positioning (DP) training and certification scheme by the Nautical Institute were used for the research. Since the oil price began to drop by the end of 2014, the oil and gas industry had to make some readjustments to keep the profits and continue in the business. The offshore DP training was affected by this crisis in two ways: the number of candidates starting the certification scheme dropped significantly; and on the other hand, candidates who had already begun the scheme were unable to complete the required number of days to be able to access the DP Simulator course, or for obtaining the DP Operator certificate. During this period, the training and certification scheme has undergone some changes to adapt to the new situation and to try to resolve the problems mentioned above. The analysis of the data shows that the effect of the oil price drop was not initially affecting the training but only began to show the consequences after some months

    Effect of oxidizing and reducing atmospheres on Ba(Ti0.90Zr0.10)O3:2V ceramics as characterized by piezoresponse force microscopy

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    The effect of annealing atmospheres (At amb, N2 and O2) on the electrical properties of Ba(Ti0.90Zr0.10)O3:2V (BZT10:2V) ceramics obtained by the mixed oxide method was investigated. X-ray photoelectron spectroscopy (XPS) analysis indicates that oxygen vacancies present near Zr and Ti ions reduce ferroelectric properties, especially in samples treated in an ambient atmosphere (At amb). BZT10:2V ceramics sintered in a nitrogen atmosphere showed better dielectric behaviour at room temperature with a dielectric permittivity measured at a frequency of 10 kHz equal to 16800 with dielectric loss of 0.023. Piezoelectric force microscopy (PFM) images reveal improvement in the piezoelectric coefficient by sintering the sample under nitrogen atmosphere. Thus, BZT10:2V ceramics sintered under a nitrogen atmosphere can be useful for practical applications which include nonvolatile digital memories, spintronics and data-storage media
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