657 research outputs found

    DEVELOPMENT OF A NUMERICAL MODEL FOR THE STUDY OF AN OSCILLATING WATER COLUMN DEVICE CONSIDERING AN IMPULSE TURBINE

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    The present work brings a numerical study of an energy conversion device which takes energy from the waves through an oscillating water column (OWC), considering an impulse turbine with rotation in the chimney region through the implementation of a movable mesh model. More precisely, a turbulent, transient and incompressible air flow is numerically simulated in a two-dimensional domain, which mimics an OWC device chamber. The objectives are the verification of the numerical model with movable mesh of the impulse turbine in the free domain from the comparison with the literature and, later, the study of the impulse turbine inserted in the geometry of the OWC device. In order to perform the numerical simulation on the generated domains, the Finite Volume Method (FVM) is used to solve the mass and momentum conservation equations. For the closure of the turbulence, the URANS (Unsteady Reynolds Averaged Navier-Stokes) model k-ω SST is used. To verify the numerical model employed, drag coefficients, lift, torque and power are obtained and compared with studies in the literature. The simulations are performed considering a flow with a Reynolds number of ReD = 867,000, air as the working fluid and a tip speed ratio of λ = 2. For the verification case, coefficients similar to those previously predicted in the literature were obtained. For the case where the OWC device was inserted it was possible to observe an intensification of the field of velocities in the turbine region, which led to an augmentation in the magnitude of all coefficients investigated (drag, lift, torque and power). For the case studied with the tip velocity ratio λ = 2, results indicated that power coefficient was augmented, indicating that the insertion of the turbine in a closed enclosure can benefit the energy conversion in an OWC device

    Examination of Several Physiological and Psychosocial Factors Potentially Associated With Masked Hypertension Among Low-Risk Adults

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    We examined the association of factors in addition to prehypertensive office blood pressure (BP) level that might improve detection of masked hypertension (MH, defined as non-elevated office BP with elevated out-of-office BP average) among those otherwise at low-risk. This sample of 340 untreated adults 30 years and older with office BP average <140/90 mmHg all had two sets of paired office BP measurements and 24-hour ambulatory BP monitoring (ABPM) sessions one week apart. Other than BP levels, the only factors that were associated (at P<0.10) with MH at both sets were male sex (75% vs 66%) and working outside the home (72% vs 59% first set; 71% vs 45% second set). Adding these variables to BP level in the model did not appreciably improve detection of MH. We found no demographic, clinical, or psychosocial measures that improved upon prehypertension as a potential predictor of MH in this sample

    Signature of chaos in gravitational waves from a spinning particle

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    A spinning test particle around a Schwarzschild black hole shows a chaotic behavior, if its spin is larger than a critical value. We discuss whether or not some peculiar signature of chaos appears in the gravitational waves emitted from such a system. Calculating the emitted gravitational waves by use of the quadrupole formula, we find that the energy emission rate of gravitational waves for a chaotic orbit is about 10 times larger than that for a circular orbit, but the same enhancement is also obtained by a regular "elliptic" orbit. A chaotic motion is not always enhance the energy emission rate maximally. As for the energy spectra of the gravitational waves, we find some characteristic feature for a chaotic orbit. It may tell us how to find out a chaotic behavior of the system. Such a peculiar behavior, if it will be found, may also provide us some additional informations to determine parameters of a system such as a spin.Comment: 14 pages, LaTeX, to appear in Phys. Rev.

    Evidence of Planetesimal infall on to the very young Herbig Be star LkHα_\alpha234

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    We report here the first evidence for planetesimal infall onto the very young Herbig Be star LkHα_\alpha234. These results are based on observations acquired over 31 days using spectroscopy of the sodium D lines, the He I 5876\AA, and hydrogen Hα_\alpha lines. We find Redshifted Absorption Components (RAC) with velocities up to 200 km/s and very mild Blueshifted Absorption Components (BEC) up to 100 km/s in the Na I lines. No correlation is observed between the appearance of the Na I RAC & BEC and the Hα_\alpha and He I line variability, which suggests that these (Na I RAC & BEC) are formed in a process unrelated to the circumstellar gas accretion. We interpret the Na I RAC as evidence for an infalling evaporating body, greater than 100 km in diameter, which is able to survive at distances between 2.0 to 0.1 AU from the star. The dramatic appearance of the sodium RAC and mild BEC is readily explained by the dynamics of this infalling body making LkHα_\alpha234 the youngest (age \sim 0.1 Myr) system with evidence for the presence of planetesimals.Comment: Accepted for publications in ApJLetter

    Polymorphous Si thin films from radio frequency plasmas of SiH4 diluted in Ar: A study by transmission electron microscopy and Raman spectroscopy

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    In this study, we present a detailed structural characterization by means of transmission electron microscopy and Raman spectroscopy of polymorphous silicon (pm-Si:H) thin films deposited using radio-frequency dust-forming plasmas of SiH4 diluted in Ar. Square-wave modulation of the plasma and gas temperature was varied to obtain films with different nanostructures. Transmission electron microscopy and electron diffraction have shown the presence of Si crystallites of around 2 nm in the pm-Si:H films, which are related to the nanoparticles formed in the plasma gas phase coming from their different growth stages, named particle nucleation and coagulation. Raman scattering has proved the role of the film nanostructure in the crystallization process induced ¿in situ¿ by laser heating

    Sequential Loading of Cohesin Subunits during the First Meiotic Prophase of Grasshoppers

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    The cohesin complexes play a key role in chromosome segregation during both mitosis and meiosis. They establish sister chromatid cohesion between duplicating DNA molecules during S-phase, but they also have an important role during postreplicative double-strand break repair in mitosis, as well as during recombination between homologous chromosomes in meiosis. An additional function in meiosis is related to the sister kinetochore cohesion, so they can be pulled by microtubules to the same pole at anaphase I. Data about the dynamics of cohesin subunits during meiosis are scarce; therefore, it is of great interest to characterize how the formation of the cohesin complexes is achieved in order to understand the roles of the different subunits within them. We have investigated the spatio-temporal distribution of three different cohesin subunits in prophase I grasshopper spermatocytes. We found that structural maintenance of chromosome protein 3 (SMC3) appears as early as preleptotene, and its localization resembles the location of the unsynapsed axial elements, whereas radiation-sensitive mutant 21 (RAD21) (sister chromatid cohesion protein 1, SCC1) and stromal antigen protein 1 (SA1) (sister chromatid cohesion protein 3, SCC3) are not visualized until zygotene, since they are located in the synapsed regions of the bivalents. During pachytene, the distribution of the three cohesin subunits is very similar and all appear along the trajectories of the lateral elements of the autosomal synaptonemal complexes. However, whereas SMC3 also appears over the single and unsynapsed X chromosome, RAD21 and SA1 do not. We conclude that the loading of SMC3 and the non-SMC subunits, RAD21 and SA1, occurs in different steps throughout prophase I grasshopper meiosis. These results strongly suggest the participation of SMC3 in the initial cohesin axis formation as early as preleptotene, thus contributing to sister chromatid cohesion, with a later association of both RAD21 and SA1 subunits at zygotene to reinforce and stabilize the bivalent structure. Therefore, we speculate that more than one cohesin complex participates in the sister chromatid cohesion at prophase I

    A novel combined scientific and artistic approach for the advanced characterization of interactomes: The akirin/subolesin model

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    The main objective of this study was to propose a novel methodology to approach challenges in molecular biology. Akirin/Subolesin (AKR/SUB) are vaccine protective antigens and are a model for the study of the interactome due to its conserved function in the regulation of different biological processes such as immunity and development throughout the metazoan. Herein, three visual artists and a music professor collaborated with scientists for the functional characterization of the AKR2 interactome in the regulation of the NF-¿B pathway in human placenta cells. The results served as a methodological proof-of-concept to advance this research area. The results showed new perspectives on unexplored characteristics of AKR2 with functional implications. These results included protein dimerization, the physical interactions with different proteins simultaneously to regulate various biological processes defined by cell type-specific AKR– protein interactions, and how these interactions positively or negatively regulate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-¿B) signaling pathway in a biological context-dependent manner. These results suggested that AKR2-interacting proteins might constitute suitable secondary transcription factors for cell-and stimulus-specific regulation of NF-¿B. Musical perspective supported AKR/SUB evolutionary conservation in different species and provided new mechanistic insights into the AKR2 interactome. The combined scientific and artistic perspectives resulted in a multidisciplinary approach, advancing our knowledge on AKR/SUB interactome, and provided new insights into the function of AKR2–protein interactions in the regulation of the NF-¿B pathway. Additionally, herein we proposed an algorithm for quantum vaccinomics by focusing on the model proteins AKR/SUB. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

    Sequential Loading of Cohesin Subunits during the First Meiotic Prophase of Grasshoppers

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    A previous version of this article appeared as an Early Online Release on January 2, 2007 (doi:10.1371/journal.pgen.0030028.eor).The cohesin complexes play a key role in chromosome segregation during both mitosis and meiosis. They establish sister chromatid cohesion between duplicating DNA molecules during S-phase, but they also have an important role during postreplicative double-strand break repair in mitosis, as well as during recombination between homologous chromosomes in meiosis. An additional function in meiosis is related to the sister kinetochore cohesion, so they can be pulled by microtubules to the same pole at anaphase I. Data about the dynamics of cohesin subunits during meiosis are scarce; therefore, it is of great interest to characterize how the formation of the cohesin complexes is achieved in order to understand the roles of the different subunits within them. We have investigated the spatio-temporal distribution of three different cohesin subunits in prophase I grasshopper spermatocytes. We found that structural maintenance of chromosome protein 3 (SMC3) appears as early as preleptotene, and its localization resembles the location of the unsynapsed axial elements, whereas radiation-sensitive mutant 21 (RAD21) (sister chromatid cohesion protein 1, SCC1) and stromal antigen protein 1 (SA1) (sister chromatid cohesion protein 3, SCC3) are not visualized until zygotene, since they are located in the synapsed regions of the bivalents. During pachytene, the distribution of the three cohesin subunits is very similar and all appear along the trajectories of the lateral elements of the autosomal synaptonemal complexes. However, whereas SMC3 also appears over the single and unsynapsed X chromosome, RAD21 and SA1 do not. We conclude that the loading of SMC3 and the non-SMC subunits, RAD21 and SA1, occurs in different steps throughout prophase I grasshopper meiosis. These results strongly suggest the participation of SMC3 in the initial cohesin axis formation as early as preleptotene, thus contributing to sister chromatid cohesion, with a later association of both RAD21 and SA1 subunits at zygotene to reinforce and stabilize the bivalent structure. Therefore, we speculate that more than one cohesin complex participates in the sister chromatid cohesion at prophase I.This work was supported by grants BFU2005–05668-C03–01, BFU2006–06655, BFU2005–01266, BFU2005–02431, and BFU2006–04406 from Ministerio de Educación y Ciencia, España, and grants 1001160016 and 11/BCB/013 from Universidad Autónoma de Madrid and Comunidad de Madrid. The Department of Immunology and Oncology was founded and is supported by the Spanish Council for Scientific Research (CSIC).Peer reviewe

    Different Measures, Different Outcomes? A Systematic Review of Performance-Based versus Self-Reported Measures of Health Literacy and Numeracy

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    BACKGROUND Health literacy (HL) and numeracy are measured by one of two methods: performance on objective tests or self-report of one’s skills. Whether results from these methods differ in their relationship to health outcomes or use of health services is unknown. METHODS We performed a systematic review to identify and evaluate articles that measured both performance-based and self-reported HL or numeracy and examined their relationship to health outcomes or health service use. To identify studies, we started with an AHRQ-funded systematic review of HL and health outcomes. We then looked for newer studies by searching MEDLINE from 1 February 2010 to 9 December 2014. We included English language studies meeting pre-specified criteria. Two reviewers independently assessed abstracts and studies for inclusion and graded study quality. One reviewer abstracted information from included studies while a second checked content for accuracy. RESULTS We identified four “fair” quality studies that met inclusion criteria for our review. Two studies measuring HL found no differences between performance-based and self-reported HL for association with self-reported outcomes (including diabetes, stroke, hypertension) or a physician-completed rheumatoid arthritis disease activity score. However, HL measures were differentially related to a patient-completed health assessment questionnaire and to a patient’s ability to interpret their prescription medication name and dose from a medication bottle. Only one study measured numeracy and found no difference between performance-based and self-reported measures of numeracy and colorectal cancer (CRC) screening utilization. However, in a moderator analysis from the same study, performance-based and self-reported numeracy were differentially related to CRC screening utilization when stratified by certain patient–provider communication behaviors (e.g., the chance to always ask questions and get the support that is needed). DISCUSSION Most studies found no difference in the relationship between results of performance-based and self-reported measures and outcomes. However, we identified few studies using multiple instruments and/or objective outcomes
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