5,900 research outputs found

    Pulsar Prospects for the Cherenkov Telescope Array

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    In the last few years, the Fermi-LAT telescope has discovered over a 100 pulsars at energies above 100 MeV, increasing the number of known gamma-ray pulsars by an order of magnitude. In parallel, imaging Cherenkov telescopes, such as MAGIC and VERITAS, have detected for the first time VHE pulsed gamma-rays from the Crab pulsar. Such detections have revealed that the Crab VHE spectrum follows a power-law up to at least 400 GeV, challenging most theoretical models, and opening wide possibilities of detecting more pulsars from the ground with the future Cherenkov Telescope Array (CTA). In this contribution, we study the capabilities of CTA for detecting Fermi pulsars. For this, we extrapolate their spectra with "Crab-like" power-law tails in the VHE range, as suggested by the latest MAGIC and VERITAS results.Comment: 4 pages, 3 figures. In Proceedings of the 2012 Heidelberg Symposium on High Energy Gamma-Ray Astronomy. All CTA contributions at arXiv:1211.184

    The insertion/deletion in the DNA-binding region allows the discrimination and subsequent identification of the glucocorticoid receptor 1 (gr1) and gr2 nucleotide sequences in gilthead sea bream (Sparus aurata): Standardizing the gr nomenclature for a better understanding of the stress response in teleost fish species

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    Cortisol carries out its physiological mechanism of action through the recognition by the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR) 1 (GR1) and GR2. Previous studies reported that the main difference between gr1 and gr2 nucleotide sequences resides in a 27-nucleotide insertion/deletion in the DNA-binding region, respectively. However, in gilthead sea bream (Sparus aurata) the annotation for gr1 and gr2 seems contradictory. The gr2 sequence possesses the characteristic 27-nucleotide insertion that, in fact, is associated with the gr1 nucleotide sequence. Thus, this study aimed to elucidate the nucleotide sequences for the gr1 and gr2 in gilthead sea bream. The Clustal Omega alignment for different fish species corroborated the presence of such 27-nucleotide insertion/deletion in the DNA-binding region for gr1 and gr2, respectively. Then, we design specific primers set for the amplification of the gilthead sea bream gr1 by polymerase chain reaction (PCR). Importantly, the gr1 nucleotide partial sequence has a high similarity with other gr1 sequences already published for other fish species, being present in all of them the 27-nucleotide insertion in the DNA-binding region. We also detected that in European sea bass the gr1 and gr2 sequences had not been named according to the 27-nucleotide insertion/deletion criteria in the DNA-binding region. Thus, our study makes an urgent call to the scientific community to discuss the establishment of an updated agreement that allows homogenizing the criteria for the nomenclature defining the gr1 and gr2 nucleotide sequences for a better understanding of the stress response in teleost fish species.This study thanks to the AGL2016-76069-C2-2- R, PID2020-117557RB-C21, PID2020-117557RB-C22 grants (AEI-MINECO; Spain). EV-V thanks the support of Fondecyt iniciacion grant (project number 11221308; Agencia Nacional de Investigacion y Desarrollo de Chile, Government of Chile). AK was the recipient of a Ministry of Science, Research, and Technology (Iran) fellowship. MT thanks for the support of the post-doctoral fellowship "Ramon y Cajal" (ref. RYC2019-026841-I) (Ministerio de Ciencia e Innovacion, Spanish Government). FER-L thanks the support of Fondecyt regular grant (project number: 1211841; Agencia Nacional de Investigacion y Desarrollo de Chile, Government of Chile)

    The gene expression profile of the glucocorticoid receptor 1 (gr1) but not gr2 is modulated in mucosal tissues of gilthead sea bream (Sparus aurata) exposed to acute air-exposure stress

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    The perception of an acute stressor (short-duration; high-intensity) induces a physiological response that activates the hypothalamic-pituitary-interrenal (HPI) axis and the subsequent release of cortisol. Cortisol carries out its effect at the molecular level through its recognition by the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). Recently, we unveiled the nucleotide sequence of the glucocorticoid receptor 1 (gr1) and gr2 in gilthead sea bream (Sparus aurata). Importantly, GR1 and GR2 respond to different levels of cortisol concentration in fish and, consequently, play a differential role in the stress response. To date, and despite their relevance, no data describes the modulation of these receptors in response to an acute stressor in gilthead sea bream (S. aurata). In this study, we evaluated the kinetics of modulation of cortisol receptors expression (gr1, gr2, mr), and its similarity with the expression pattern of selected genes associated with stress (hsp70; enolase) and immune response (lysozyme; c3; il-1 beta; tnf-alpha; il-10; tgf-beta 1) in gilthead sea bream mucosal tissues (skin; gills; anterior gut). To do it, fish were acutely stressed by three-minute air exposure, and the expression profile was evaluated at zero, 1 h, 6 h, and 24 h post-stress (hps). The cortisol level in plasma and skin mucus peaked at 1 hps. All the mucosal tissues showed a time-dependent and tissue-specific upregulation of gr1 and mr. The immune-related genes showed the upregulation of il-1 beta at 6 hps (gills; anterior gut), and tnf-alpha and c3 at 24 hps (anterior gut). Taking together, our study concludes that fish subjected to three-minute air exposure modulated the expression of gr1 but not gr2 in mucosal tissues (skin; gills; anterior gut). Furthermore, our data reinforce the idea of a stimulatory effect induced in genes associated with the innate immune response after acute stress but focused at the mucosal level and in a time- and tissue-dependent manner

    Effects of Gamma Irradiation on Curcumin

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    In this study, remnants concentrations of curcumin in Curcuma longa (organic turmeric powder) were determined after it was exposed to irradiation doses of 1, 2 and 3 kGy. Curcumin analysis was performed using the analyte-sensitive impulse differential polarography technique (LOD: 0.621 ppm and LOQ: 2.130 ppm). The results obtained showed a decreasing concentration of curcumin as a function of the irradiation dose. This reduction is low in terms of affecting the product’s quality with respect to its concentration

    A lean six sigma framework for continuous and incremental improvement in the oil and gas sector

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    This article aims to explore synergies between Lean Production (LP) and Six Sigma principles in order to propose a Lean Six Sigma (LSS) framework for continuous and incremental improvement in the oil and gas sector. The Three-Dimensional LSS Framework seeks to provide various combinations about the integration between LP principles, DMAIC cycle and PDCA cycle to support operations management needs. Design/methodology/approach - The research method is composed of two main steps: (i) diagnostic of current problems and proposition of a conceptual framework that qualitatively integrates synergistic aspects of LP and Six Sigma; and (ii) analysis of the application of the construct through semi-structured interviews with leaders from oil and gas companies to assess and validate the proposed framework. Findings - As a result, a conceptual framework of LSS is developed contemplating the integration of LP and Six Sigma and providing a systemic and holistic approach to problemsolving through continuous and incremental improvement in the oil and gas sector. Originality/value - This research is different from previous studies because it integrates LP principles, DMAIC and PDCA cycles into a unique framework that fulfils a specific need of oil and gas sector. It presents a customized LSS framework that guides wastes and costs reduction, while enhances quality and reduces process variability to elevate efficiency in operations management of this sector. The paper type is an original research that present new and original scientific findings.N/

    Spectroscopic Observations of Convective Patterns in the Atmospheres of Metal-Poor Stars

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    Convective line asymmetries in the optical spectrum of two metal-poor stars, Gmb1830 and HD140283, are compared to those observed for solar metallicity stars. The line bisectors of the most metal-poor star, the subgiant HD140283, show a significantly larger velocity span that the expectations for a solar-metallicity star of the same spectral type and luminosity class. The enhanced line asymmetries are interpreted as the signature of the lower metal content, and therefore opacity, in the convective photospheric patterns. These findings point out the importance of three-dimensional convective velocity fields in the interpretation of the observed line asymmetries in metal-poor stars, and in particular, urge for caution when deriving isotopic ratios from observed line shapes and shifts using one-dimensional model atmospheres. The mean line bisector of the photospheric atomic lines is compared with those measured for the strong Mg I b1 and b2 features. The upper part of the bisectors are similar, and assuming they overlap, the bottom end of the stronger lines, which are formed higher in the atmosphere, goes much further to the red. This is in agreement with the expected decreasing of the convective blue-shifts in upper atmospheric layers, and compatible with the high velocity redshifts observed in the chromosphere, transition region, and corona of late-type stars.Comment: 27 pages, LaTeX; 10 Figures (14 PostScript files); to be published in The Astrophysical Journa

    Temporal patterns in coral reef, seagrass and mangrove communities from Chengue bay CARICOMP site (Colombia): 1993-2008

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    Few monitoring programs have simultaneously assessed the dynamics of linked marine ecosystems (coral reefs, seagrass beds and mangroves) to document their temporal and spatial variability. Based on CARICOMP protocol we evaluated permanent stations in coral reefs, seagrass beds and mangroves from 1993 to 2008 in Chengue Bay at the Tayrona Natural Park, Colombian Caribbean. Overall, the studied ecosystems showed a remarkable stability pattern over the monitoring period. While there were annual variations in coral reefs (coral cover) and mangroves (litterfall) caused by hurricane Lenny in 1999, particular trends in seagrass (leaf area index and leaf productivity) appear to reflect the natural variability in this ecosystem. We suggest that monitoring sites at the three marine ecosystems had in general a healthy development in the last 16 years. Our results are critical to locally improve the management strategies (Tayrona Natural Park) and to understand the long-term dynamics of closely associated marine ecosystems in the Caribbean. Copyright © 2011 Elsevier B.V. All rights reserved

    Performance Evaluation of Face Mask Detection for Real-Time Implementation on an RPi

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    Mask-wearing remains to be one of the primary protective measures against COVID-19. To address the difficulty of manual compliance monitoring, face mask detection models considerate of both frontal and angled faces were developed. This study aimed to test the performance of the said models in classifying multi-face images and upon running on a Raspberry Pi device. The accuracies and inference speeds were measured and compared when inferencing images with one, two, and three faces and on the desktop and the Raspberry Pi. With an increasing number of faces in an image, the models’ accuracies were observed to decline, while their speeds were not significantly affected. Moreover, the YOLOv5 Small model was regarded to be potentially the best model for use on lower resource platforms, as it experienced a 3.33% increase in accuracy and recorded the least inference time of two seconds per image among the models
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