967 research outputs found

    Mixed-effects high-dimensional multivariate regression via group-lasso regularization

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    Linear mixed modeling is a well-established technique widely employed when observations possess a grouping structure. Nonetheless, this standard methodology is no longer applicable when the learning framework encompasses a multivariate response and high-dimensional predictors. To overcome these issues, in the present paper a penalized estimation procedure for multivariate linear mixed-effects models (MLMM) is introduced. In details, we propose to regularize the likelihood via a group-lasso penalty, forcing only a subset of the estimated parameters to be preserved across all components of the multivariate response. The methodology is employed to develop novel surrogate biomarkers for cardiovascular risk factors, such as lipids and blood pressure, from whole-genome DNA methylation data in a multi-center study. The described methodology performs better than current stateof- art alternatives in predicting a multivariate continuous outcome

    Interference of diffraction and transition radiation and its application as a beam divergence diagnostic

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    We have observed the interference of optical diffraction radiation (ODR) and optical transition radiation (OTR) produced by the interaction of a relativistic electron beam with a micromesh foil and a mirror. The production of forward directed ODR from electrons passing through the holes and wires of the mesh and their separate interactions with backward OTR from the mirror are analyzed with the help of a simulation code. By careful choice of the micromesh properties, mesh-mirror spacing, observation wavelength and filter band pass, the interference of the ODR produced from the unperturbed electrons passing through the open spaces of the mesh and OTR from the mirror are observable above a broad incoherent background from interaction of the heavily scattered electrons passing through the mesh wires. These interferences (ODTRI) are sensitive to the beam divergence and can be used to directly diagnose this parameter. We compare experimental divergence values obtained using ODTRI, conventional OTRI, for the case when front foil scattering is negligible, and computed values obtained from transport code calculations and multiple screen beam size measurements. We obtain good agreement in all cases.Comment: 40 pages 18 Figures. accepted for publication in PRSTA

    Camouflage during movement in the European cuttlefish (Sepia officinalis)

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    A moving object is considered conspicuous because of the movement itself. When moving from one background to another, even dynamic camouflage experts such as cephalopods should sacrifice their extraordinary camouflage. Therefore, minimizing detection at this stage is crucial and highly beneficial. In this study, we describe a background-matching mechanism during movement, which aids the cuttlefish to downplay its presence throughout movement. In situ behavioural experiments using video and image analysis, revealed a delayed, sigmoidal, colour-changing mechanism during movement of Sepia officinalis across uniform black and grey backgrounds. This is a first important step in understanding dynamic camouflage during movement, and this new behavioural mechanism may be incorporated and applied to any dynamic camouflaging animal or man-made system on the move.info:eu-repo/semantics/publishedVersio

    Age validation in common octopus Octopus vulgaris using stylet increment analysis

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    6 páginas, 1 tabla, 3 figurasDaily periodicity of growth increments in stylets was validated in wild-caught Octopus vulgaris maintained under controlled conditions. It was corroborated by staining the stylets either with oxytetracycline (OTC) or tetracycline (TC), and comparing the number of rings produced with the number of days elapsed. In all, 19 animals (10 males and 9 females; 680–1470 g body weight, BW) were injected with OTC in Vigo (mean 124 mg kg−1), and another six animals (1 male and 5 females; 248–570 g BW) with TC at Naples (mean 120 mg kg−1). The animals were successfully maintained in captivity until sacrificed for up to 6 (one animal), 9 (one animal), 18 (the six animals from Naples), and 21 (17 animals) days. The number of increments counted in transverse stylet sections was 18.9 ± 1.4 and 20.5 ± 1.5 for octopuses maintained for 18 and 21 d, respectively. The mean rate of increment formation was 1.02 increments per day, suggesting a periodicity of 1 increment per day in the stylet. Consequently, the results successfully validate daily increment deposition in O. vulgaris stylets in the size range analysedThe research was supported by ECOSUMMER (European Union), and CAH received early training ECOSUMMER (Marie Curie Action) supportPeer reviewe

    Metacestodes of elasmobranch tapeworms in octopus vulgaris (Mollusca, cephalopoda) from central mediterranean—SEM and molecular data

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    Cephalopods are intermediate/paratenic hosts in the life cycle of elasmobranch tapeworms, nevertheless most records of infection in this group of mollusks are outdated and fragmentary. The present work aimed to investigate the cestode fauna of the common octopus Octopus vulgaris from the Tyrrhenian Sea (Central Mediterranean). The parasitic stages were characterized by light and Scanning Electron Microscopy (SEM) and sequencing of 28S rDNA. Three cestode taxa were identified to the genus level: the onchoproteocephalidean Acanthobothrium sp. (prevalence 28%), the “tetraphyllidean” Anthobothrium sp. (prevalence 13%) and the trypanorhynch Nybelinia sp. (prevalence 3%). The remarkable prevalence observed for gastrointestinal cestodes highlight a possible important role of O. vulgaris in the transmission of elasmobranch tapeworms, particularly Onchoproteocephalideans. Furthermore, the present work provides, for the first time, detailed morphological (SEM) and molecular support to confirm the occurrence of Anthobothrium sp. in cephalopod hosts. In order to gain higher taxonomic resolution for the identified taxa, we stress the need to collect further morphological and molecular data of adult cestodes infecting their elasmobranch definitive hosts

    Pobreza personal y pobreza institucional

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    Multi-component measurements of the Jefferson Lab energy recovery linac electron beam using optical transition and diffraction radiation

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    High brightness electron accelerators, such as energy recovery linacs (ERL), often have complex particle distributions that can create difficulties in beam transport as well as matching to devices such as wigglers used to generate radiation from the beam. Optical transition radiation (OTR), OTR interferometry (OTRI) and optical diffraction-transition radiation interferometry (ODTRI) have proven to be effective tools for diagnosing both the spatial and angular distributions of charged particle beams. OTRI and ODTRI have been used to measure rms divergences and optical transverse phase space mapping has been demonstrated using OTRI. In this work we present the results of diagnostic experiments using OTR and ODR conducted at the Jefferson Laboratory 115 MeV ERL which show the presence of two separate components within the spatial and angular distributions of the beam. By assuming a correlation between the spatial and angular features we estimate an rms emittance value for each of the two components.Comment: 25 pages, 10 figures; accepted for publication in PRSTAB; minor formatting errors correcte

    Union effectiveness: In Search of the Holy Grail

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    YesThis article revisits the concept of union effectiveness and proposes a conceptual model to inform its study and application. Previous conceptual and empirical work is examined to identify key strengths and weaknesses, and to relate the union effectiveness concept to union renewal and other key concepts. This leads to the proposal of a Goal-System framework that builds and improves on prior research
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