72 research outputs found

    Thermal photon production in a strongly coupled anisotropic plasma

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    Photons produced in heavy ion collisions escape virtually unperturbed from the surrounding medium, thus representing an excellent probe of the conditions at the emission point. Using the gauge/gravity duality, we calculate the rate of photon production in an anisotropic, strongly coupled N=4 plasma with Nf<<Nc quark flavors. We consider arbitrary orientations of the photon momentum with respect to the anisotropic direction, as well as arbitrary values of the anisotropy. We present results for the correlation functions of two electromagnetic currents and for the electric conductivity. These quantities can be larger or smaller than the isotropic ones, depending on the direction of propagation and polarization of the photons. The total production rate is however always larger than the isotropic one, independently of the frequency, direction of propagation, and value of the anisotropy.Comment: 27 pages, 13 figures; v2: minor changes, added reference

    More on thermal probes of a strongly coupled anisotropic plasma

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    We extend the analysis of 1211.2199, where the photon production rate of an anisotropic strongly coupled plasma with Nf<<Nc massless quarks was considered. We allow here for non-vanishing quark masses and study how these affect the spectral densities and conductivities. We also compute another important probe of the plasma, the dilepton production rate. We consider generic angles between the anisotropic direction and the photon and dilepton wave vectors, as well as arbitrary quark masses and arbitrary values of the anisotropy parameter. Generically, the anisotropy increases the production rate of both photons and dileptons, compared with an isotropic plasma at the same temperature.Comment: 41 pages, 24 figures; v2: minor changes, added references; v3: added reference. Extends arXiv:1211.219

    Scale Prototype Ring Main Unit for the Measurement and Control of Nodes in a Smart Grid

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    Smart grids are playing a key role in modern electric power grids, improving load control, assuring safer operations and collecting valuable information of the electrical conditions of the grid. In a smart grid, a RTU (Remote Terminal Unit) is a device that is able to measure the electric variables of the grid and sends all the information to a MTU (Master Terminal Unit), which is responsible of controlling the operations of the grid. RMU (Ring Main Unit) devices are used in electric power grids to protect loads and to disconnect them in case of failure to prevent damage. This article presents the design of a special RMU capable of measuring voltage, current and frequency, detecting electric faults, and making automatic self-healing in order to manage the flow of energy in the smart grid to guarantee energy supply to the critical loads (hospitals). The RMU devices were installed on a scaled smart grid in order to show its operation capabilities

    A clone-free, single molecule map of the domestic cow (Bos taurus) genome.

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    BackgroundThe cattle (Bos taurus) genome was originally selected for sequencing due to its economic importance and unique biology as a model organism for understanding other ruminants, or mammals. Currently, there are two cattle genome sequence assemblies (UMD3.1 and Btau4.6) from groups using dissimilar assembly algorithms, which were complemented by genetic and physical map resources. However, past comparisons between these assemblies revealed substantial differences. Consequently, such discordances have engendered ambiguities when using reference sequence data, impacting genomic studies in cattle and motivating construction of a new optical map resource--BtOM1.0--to guide comparisons and improvements to the current sequence builds. Accordingly, our comprehensive comparisons of BtOM1.0 against the UMD3.1&nbsp;and Btau4.6 sequence builds tabulate large-to-immediate scale discordances requiring mediation.ResultsThe optical map, BtOM1.0, spanning the B. taurus genome (Hereford breed, L1 Dominette 01449) was assembled from an optical map dataset consisting of 2,973,315 (439 X; raw dataset size before assembly) single molecule optical maps (Rmaps; 1 Rmap = 1 restriction mapped DNA molecule) generated by the Optical Mapping System. The BamHI map spans 2,575.30&nbsp;Mb and comprises 78 optical contigs assembled by a combination of iterative (using the reference sequence: UMD3.1) and de novo assembly techniques. BtOM1.0 is a high-resolution physical map featuring an average restriction fragment size of 8.91&nbsp;Kb. Comparisons of BtOM1.0 vs. UMD3.1, or Btau4.6, revealed that Btau4.6 presented far more discordances (7,463) vs. UMD3.1 (4,754). Overall, we found that Btau4.6 presented almost double the number of discordances than UMD3.1 across most of the 6 categories of sequence vs. map discrepancies, which are: COMPLEX (misassembly), DELs (extraneous sequences), INSs (missing sequences), ITs (Inverted/Translocated sequences), ECs (extra restriction cuts) and MCs (missing restriction cuts).ConclusionAlignments of UMD3.1 and Btau4.6 to BtOM1.0 reveal discordances commensurate with previous reports, and affirm the NCBI's current designation of UMD3.1 sequence assembly as the "reference assembly" and the Btau4.6 as the "alternate assembly." The cattle genome optical map, BtOM1.0, when used as a comprehensive and largely independent guide, will greatly assist improvements to existing sequence builds, and later serve as an accurate physical scaffold for studies concerning the comparative genomics of cattle breeds

    Optimal Strategy to Exploit the Flexibility of an Electric Vehicle Charging Station

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    The increasing use of electric vehicles connected to the power grid gives rise to challenges in the vehicle charging coordination, cost management, and provision of potential services to the grid. Scheduling of the power in an electric vehicle charging station is a quite challenging task, considering time-variant prices, customers with different charging time preferences, and the impact on the grid operations. The latter aspect can be addressed by exploiting the vehicle charging flexibility. In this article, a specific definition of flexibility to be used for an electric vehicle charging station is provided. Two optimal charging strategies are then proposed and evaluated, with the purpose of determining which strategy can offer spinning reserve services to the electrical grid, reducing at the same time the operation costs of the charging station. These strategies are based on a novel formulation of an economic model predictive control algorithm, aimed at minimising the charging station operation cost, and on a novel formulation of the flexibility capacity maximisation, while reducing the operation costs. These formulations incorporate the uncertainty in the arrival time and state of charge of the electric vehicles at their arrival. Both strategies lead to a considerable reduction of the costs with respect to a simple minimum time charging strategy, taken as the benchmark. In particular, the strategy that also accounts for flexibility maximisation emerges as a new tool for maintaining the grid balance giving cost savings to the charging stations

    Parameters Identification and Gas Behavior Characterization of DBD Systems

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    This paper proposes an efficient modeling and an identification method for dielectric barrier discharge (DBD) systems, based on input–output (current–voltage) experimental measurements. The DBD is modeled using an equivalent electric circuit associated with a differential equation that describes the dynamics of its conductance. This equation assumes a homogeneous behavior of the gas. This paper introduces a series of polynomial terms of the current of the gas into the conductance equation. These terms, after identification, are a very useful tool to analyze the physical mechanisms that take place in the gas. The identification process also returns the numerical values of other DBD parameters, such as associated capacitances and the breakdown voltage. In addition, an asymmetric model for the gas, which considers the direction of the current, is proposed to consider the possible geometrical dissimilarity between the two electrodes of the DBD setup. Experimental measurements taken on two different DBD applications are used for validating the proposed approach

    Sarcopenic dysphagia

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    La disfagia sarcopénica es la dificultad deglutoria asociada con la pérdida de masa, fuerza y función muscular generalizada. Su prevalencia aumenta en pacientes ancianos, así como en aquellos con malnutrición o con desuso de la musculatura deglutoria. Está relacionada con desenlaces adversos, como lo son la neumonía aspirativa, la acumulación de residuos en la cavidad orofaríngea luego de la deglución, la peor calidad de vida y los tiempos de estancia hospitalaria prolongados. Se realizó una revisión de la literatura disponible sobre el tema con el fin de proveer una guía para la detección temprana y el manejo de esta entidad clínica, necesarios para una adecuada práctica clínica.Q4Sarcopenic dysphagia is a swallowing difficulty associated with loss of mass, strength and generalized muscular function. Its prevalence is higher among elderly patients and those with malnutrition or with disuse of the swallowing musculature. It is associated with adverse outcomes such as aspiration pneumonia and accumulation of waste in the oropharyngeal cavity after swallowing as well as with poor quality of life and prolonged hospital stays. A review of the literature available on the subject was done in order to provide a guide for early detection and management of this clinical entity which is needed for clinical practice.https://orcid.org/0000-0003-4911-3869https://orcid.org/0000-0001-5832-0603https://orcid.org/0000-0001-8260-9108https://orcid.org/0000-0002-8584-3191N/

    Characterization of rice yield based on biomass and SPAD-based leaf nitrogen for large genotype plots

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    The use of Unmanned Aerial Vehicle (UAV) images for biomass and nitrogen estimation offers multiple opportunities for improving rice yields. UAV images provide detailed, high-resolution visual information about vegetation properties, enabling the identification of phenotypic characteristics for selecting the best varieties, improving yield predictions, and supporting ecosystem monitoring and conservation efforts. In this study, an analysis of biomass and nitrogen is conducted on 59 rice plots selected at random from a more extensive trial comprising 400 rice genotypes. A UAV acquires multispectral reflectance channels across a rice field of subplots containing different genotypes. Based on the ground-truth data, yields are characterized for the 59 plots and correlated with the Vegetation Indices (VIs) calculated from the photogrammetric mapping. The VIs are weighted by the segmentation of the plants from the soil and used as a feature matrix to estimate, via machine learning models, the biomass and nitrogen of the selected rice genotypes. The genotype IR 93346 presented the highest yield with a biomass gain of 10,252.78 kg/ha and an average daily biomass gain above 49.92 g/day. The VIs with the highest correlations with the ground-truth variables were NDVI and SAVI for wet biomass, GNDVI and NDVI for dry biomass, GNDVI and SAVI for height, and NDVI and ARVI for nitrogen. The machine learning model that performed best in estimating the variables of the 59 plots was the Gaussian Process Regression (GPR) model with a correlation factor of 0.98 for wet biomass, 0.99 for dry biomass, and 1 for nitrogen. The results presented demonstrate that it is possible to characterize the yields of rice plots containing different genotypes through ground-truth data and VIs

    Fundamentals of active shielding based on implicit control

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    Active noise control is a methodology to attenuate low frequency noise. The attenuation is usually achieved near the sensor which is used in the controller. In order to achieve the desired attenuation inside a desired zone without locating a sensor inside, a method called active shielding can be used. It works by controlling the pressure at boundaries of the desired zone. This article presents a novel method for implementing active shielding only using pressure sensors. It is based on a new concept called implicit control, which takes into account the locations of sensors. Some simulations validate the presented method for free fields

    Sensor augmented insulin pump therapy in older adults : impact on self-rated health and glycemic control

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    Q1Q1545-547Diabetes mellitus (DM) is related to serious complicationsleading to decreased quality of life, well-being, and self-ratedhealth for both the patients and caregivers
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