2,550 research outputs found

    A Bag of Features Based Approach for Classification of Motile Sperm Cells

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    The analysis of sperm morphology remains an essential process for diagnosis and treatment of male infertility. In this paper, a novel framework based on image processing is proposed to classify sperm cell images affected by noise due to their movement. This represents a challenge, articularly because the cells are not fixed or stained. The proposed framework is based on Speeded-Up Robust Features (SURF) combined with Bag of Features (BoF) models to quantise features computed by SURF. Support Vector Machines (SVMs) are used to classify the simplified feature vectors, extracted from sperm cell images, into normal, abnormal and noncell categories. The performance of this framework is compared to a similar model where the Histogram of Oriented Gradients (HOG) is used to extract features and SVMs is applied for their classification. The proposed framework allows to achieve classification results with an average accuracy of 90% with the SURF approach compared to 78% with the HOG approach

    Effects of site dilution on the magnetic properties of geometrically frustrated antiferromagnets

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    The effect of site dilution by non magnetic impurities on the susceptibility of geometrically frustrated antiferromagnets (kagome and pyrochlore lattices) is discussed in the framework of the Generalized Constant Coupling model, for both classical and quantum Heisenberg spins. For the classical diluted pyrochlore lattice, excellent agreement is found when compared with Monte Carlo data. Results for the quantum case are also presented and discussed.Comment: 5 pages, 3 figure

    Mapeamento de solos através do caráter espectral, da rede de drenagem e da vegetação

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    This study puts together three different methodologies that utilize Remote Sensing Techniques for the study of soils. The soils of the selected area were studied by their spectra parameters and analysed through satellite images processed in an appropriate equipment. The drainage indices were correlated to their respective soils. The well known relationship between types of cerrado vegetation and associated soils were also studied. For each situation a soil map was prepared; those maps showed a reasonable relationship with the ground truth. Wen these informations were put together in a single map, the relationship with the reference soil map was highly significant, showing the applicability of the methodology.O presente trabalho reuniu três metodologias conhecidas para o estudo de solos, todas associadas às técnicas de sensoriamento remoto. Para uma mesma área, os solos foram relacionados aos seus parâmetros espectrais obtidos digitalmente de imagens de satélite; os índices de drenagem da área foram também relacionados aos respectivos solos; a conhecida relação entre tipos de cerrado e respectivos solos suporte foi também estudada. Para cada situação foi preparado um mapa de solos, que se aproximava do mapa já existente. Quando as informações de tais mapas foram agregadas em um único mapa, a aproximação com o mapa de controle foi altamente satisfatória evidenciando a aplicabilidade da metodologia

    Quantum dynamics of crystals of molecular nanomagnets inside a resonant cavity

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    It is shown that crystals of molecular nanomagnets exhibit enhanced magnetic relaxation when placed inside a resonant cavity. Strong dependence of the magnetization curve on the geometry of the cavity has been observed, providing evidence of the coherent microwave radiation by the crystals. A similar dependence has been found for a crystal placed between Fabry-Perot superconducting mirrors. These observations open the possibility of building a nanomagnetic microwave laser pumped by the magnetic field

    Genetic determinants of cellular addiction to DNA polymerase theta

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    Polymerase theta (Pol θ, gene name Polq) is a widely conserved DNA polymerase that mediates a microhomology-mediated, error-prone, double strand break (DSB) repair pathway, referred to as Theta Mediated End Joining (TMEJ). Cells with homologous recombination deficiency are reliant on TMEJ for DSB repair. It is unknown whether deficiencies in other components of the DNA damage response (DDR) also result in Pol θ addiction. Here we use a CRISPR genetic screen to uncover 140 Polq synthetic lethal (PolqSL) genes, the majority of which were previously unknown. Functional analyses indicate that Pol θ/TMEJ addiction is associated with increased levels of replication-associated DSBs, regardless of the initial source of damage. We further demonstrate that approximately 30% of TCGA breast cancers have genetic alterations in PolqSL genes and exhibit genomic scars of Pol θ/TMEJ hyperactivity, thereby substantially expanding the subset of human cancers for which Pol θ inhibition represents a promising therapeutic strategy

    Detection of apoptotic events, using different methods, in renal tissues after acute haemorrhage.

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    Apoptosis plays an important role in cellular damage caused by acute renal hypoperfusion. The aim of this study was to detect apoptotic events in an animal model of acute haemorrhage, followed by volume replacement with different intravenous solution

    Designing the club of the future with data: A case study on collaboration of creative industries

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    This paper reflects on the development of a multi-sensory clubbing experience which was deployed during a two-day event within the context of the Amsterdam Dance Event in October 2016 in Amsterdam. We present how the entire experience was developed end-to-end and deployed at the event through the collaboration of several project partners from industries such as art and design, music, food, technology and research. Central to the system are smart textiles, namely wristbands equipped with Bluetooth LE sensors which were used to sense people attending the dance event. We describe the components of the system, the development process, the collaboration between the involved entities and the event itself. To conclude the paper, we highlight insights gained from conducting a real world research deployment across many collaborators and stakeholders with different backgrounds

    Meta-Stable Supersymmetry Breaking in a Cooling Universe

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    We look at the recently proposed idea that susy breaking can be accomplished in a meta-stable vacuum. In the context of one of the simplest models (the Seiberg-dual of super-QCD), we address the following question: if we look at this theory as it cools from high temperature, is it at all possible that we can end up in a susy-breaking meta-stable vacuum? To get an idea about the answer, we look at the free energy of the system at high temperature. We conclude that the phase-structure of the free-energy as the temperature drops, is indeed such that there is a second order phase transition in the direction of the non-susy vacuum at a finite T=TcQT=T_c^Q. On the other hand, the potential barrier in the direction of the susy vacuum is there all the way till T0T \sim 0.Comment: writing full author name

    Three-Neutrino Mixing after the First Results from K2K and KamLAND

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    We analyze the impact of the data on long baseline \nu_\mu disappearance from the K2K experiment and reactor \bar\nu_e disappearance from the KamLAND experiment on the determination of the leptonic three-generation mixing parameters. Performing an up-to-date global analysis of solar, atmospheric, reactor and long baseline neutrino data in the context of three-neutrino oscillations, we determine the presently allowed ranges of masses and mixing and we consistently derive the allowed magnitude of the elements of the leptonic mixing matrix. We also quantify the maximum allowed contribution of \Delta m^2_{21} oscillations to CP-odd and CP-even observables at future long baseline experiments.Comment: Some typos correcte

    Supernova Bounds on Majoron-emitting decays of light neutrinos

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    Neutrino masses arising from the spontaneous violation of ungauged lepton-number are accompanied by a physical Goldstone boson, generically called Majoron. In the high-density supernova medium the effects of Majoron-emitting neutrino decays are important even if they are suppressed in vacuo by small neutrino masses and/or small off-diagonal couplings. We reconsider the influence of these decays on the neutrino signal of supernovae in the light of recent Super-Kamiokande data on solar and atmospheric neutrinos. We find that majoron-neutrino coupling constants in the range 3\times 10^{-7}\lsim g\lsim 2\times 10^{-5} or g \gsim 3 \times 10^{-4} are excluded by the observation of SN1987A. Then we discuss the potential of Superkamiokande and the Sudbury Neutrino Observatory to detect majoron neutrino interactions in the case of a future galactic supernova. We find that these experiments could probe majoron neutrino interactions with improved sensitivity.Comment: 28 pages, 5 figure
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