2,518 research outputs found
Descripción del Perfil Lector de una Revista CientÃfica de AudiologÃa para profesionales del área audiológica Hispanohablantes
Audiologists are recognized in Spain and most countries in Latin America and have practised in various fields for more than 40 years. Despite this, a paucity of information exists regarding audiologists’ engagement with scientific journals both as readers and authors alike. The aim of this paper was to describe the scientific-disciplinary reader profile of Spanish-speaking audiology professionals. A questionnaire was distributed online with 16 questions grouped into two sections: 1) General and demographic data and 2) Readership profile. A total of 200 questionnaires were completed. With the results, a qualitative analysis was performed and a summary was written for each question.
General audiology and hearing aids/amplification systems were found to be the areas of greatest interest among respondents (74% and 71%, respectively). In the readership profile section, 66% of respondents reported consulting scientific journals (at least once a month). The most common reason, given by 51% in this group, was to keep up to date. However, 81% of respondents reported never having published in a peer-reviewed journal. The main reason for not publishing was lack of confidence to write an article (51%). Despite audiologists showing a keen interest in reading audiology journals, only a small proportion submits articles for publication.El profesional audiólogo se encuentra reconocido en la mayorÃa de los paÃses de Iberoamérica desempeñando sus funciones en diversas áreas desde hace más de 40 años. A pesar esto aún existe escasa información en relación a la vinculación con revistas cientÃficas, ya sea como lectores y/o autores. El objetivo del presente trabajo fue la caracterización del profesional del área de la audiologÃa en Iberoamérica como lector de una revista cientÃfica de audiologÃa en Castellano. Un total de 200 cuestionarios fueron respondidos.
En relación al perfil del lector, se reporta que un 66% de los participantes consulta revistas cientÃficas (una o más veces al mes), siendo la actualización (51%) el motivo más frecuente dentro de este grupo. Sin embargo, un 81% de los participantes refiere no tener experiencia publicando en una revista revisada por pares, siendo inseguridad para escribir un artÃculo (51%) como la razón principal
Polarization States in B -> rho K* and New Physics
The standard-model explanations of the anomalously-large transverse
polarization fraction fT in B -> phi K* can be tested by measuring the
polarizations of the two decays B+ -> rho+ K*0 and B+ -> rho0 K*+. For the
scenario in which the transverse polarizations of both B -> rho K* decays are
predicted to be large, we derive a simple relation between the fT's of these
decays. If this relation is not confirmed experimentally, this would yield an
unambiguous signal for new physics. The new-physics operators which can account
for the discrepancy in B -> pi K decays will also contribute to the
polarization states of B -> rho K*. We compute these contributions and show
that there are only two operators which can simultaneously account for the
present B -> pi K and B -> rho K* data. If the new physics obeys an approximate
U-spin symmetry, the B -> phi K* measurements can also be explained.Comment: 20 pages, latex, no figures. Minor changes to references and Table 1.
Minor modification of terms; more complete description of triple-product
asymmetry. Analysis and conclusions unchange
Hydropower Advantages over Batteries in Energy Storage of Off-Grid Systems: A Case Study
Microgrids are decentralized power production systems, where the energy production and consumption are very close to each other. Microgrids generally exploit renewable energy sources, encountering a problem of storage, as the power production from solar and wind is intermittent. This research presents a new integrated methodology and discusses a comparison of batteries and pumped storage hydropower (PSH) as energy storage systems with the integration of wind and solar PV energy sources, which are the major upcoming technologies in the renewable energy sector. We implemented the simulator and optimizer model (HOMER), which develops energy availability usage to obtain optimized renewable energy integration in the microgrid, showing its economic added value. Two scenarios are run with this model—one considers batteries as an energy storage technology and the other considers PSH—in order to obtain the best economic and technical results for the analyzed microgrid. The economic analysis showed a lower net present cost (NPC) and levelized cost of energy (LCOE) for the microgrid with PSH. The results showed that the microgrid with the storage of PSH was economical, with an NPC of 45.8 M€ and an LCOE of 0.379 €/kWh, in comparison with the scenario with batteries, which had an NPC of 95.2 M€ and an LCOE of 0.786 €/kWh. The role of storage was understood by differentiating the data into different seasons, using a Python model. Furthermore, a sensitivity analysis was conducted by varying the capital cost multiplier of solar PV and wind turbines to obtain the best optimal economic solutions
Mathematic Modelling of a Reversible Hydropower System: Dynamic Effects in Turbine Mode
Over the past few years, there has been significant interest in the importance of reversible hydro-pumping systems due to their favorable flexibility and economic and environmental characteristics. When designing reversible lines, it is crucial to consider dynamic effects and corresponding extreme pressures that may occur during normal and emergency operating scenarios. This research describes essentially the turbine operation, although various boundary elements are mathematically formulated and presented to provide an understanding of the system complexity. Different numerical approaches are presented, based on the 1D method of characteristics (MOC) for the long hydraulic circuit, the dynamic turbine runner simulation technique for the behavior of the power station in turbine mode and the interaction with the fluid in the penstock, and a CFD model (2D and 3D) to analyze the flow behavior crossing the runner through the velocity fields and pressure contours. Additionally, the simulation results have been validated by experimental tests on different setups characterized by long conveyance systems, consisting of a small scale of pumps as turbines (at IST laboratory) and classical reaction turbines (at LNEC laboratory). Mathematical models, together with an intensive campaign of experiments, allow for the estimation of dynamic effects related to the extreme transient pressures, the fluid-structure interaction with rotational speed variation, and the change in the flow. In some cases, the runaway conditions can cause an overspeed of 2–2.5 of the rated rotational speed (NR) and an overpressure of 40–65% of the rated head (HR), showing significant impacts on the pressure wave propagation along the entire hydraulic circuit. Sensitivity analyses based on systematic numerical simulations of PATs (radial and axial types) and reaction turbines (Francis and Kaplan types) and comparisons with experiments are discussed. These evaluations demonstrate that the full-load rejection scenario can be dangerous for turbomachinery with low specific-speed (ns) values, in particular when associated with long penstocks and fast guide vane (or control valve) closing maneuver. © 2023 by the authors
The 21 cm Signature of Shock Heated and Diffuse Cosmic String Wakes
The analysis of the 21 cm signature of cosmic string wakes is extended in
several ways. First we consider the constraints on from the absorption
signal of shock heated wakes laid down much later than matter radiation
equality. Secondly we analyze the signal of diffuse wake, that is those wakes
in which there is a baryon overdensity but which have not shock heated. Finally
we compare the size of these signals compared to the expected thermal noise per
pixel which dominates over the background cosmic gas brightness temperature and
find that the cosmic string signal will exceed the thermal noise of an
individual pixel in the Square Kilometre Array for string tensions .Comment: 10 pages, 4 figures, Appendix added, version published in JCA
Effect of a commercial air valve on the rapid filling of a single pipeline: a numerical and experimental analysis
[EN] The filling process in water pipelines produces pressure surges caused by the compression
of air pockets. In this sense, air valves should be appropriately designed to expel sufficient air to
avoid pipeline failure. Recent studies concerning filling maneuvers have been addressed without
considering the behavior of air valves. This work shows a mathematical model developed by the
authors which is capable of simulating the main hydraulic and thermodynamic variables during
filling operations under the effect of the air valve in a single pipeline, which is based on the mass
oscillation equation, the air¿water interface, the polytropic equation of the air phase, the air mass
equation, and the air valve characterization. The mathematical model is validated in a 7.3-m-long
pipeline with a 63-mm nominal diameter. A commercial air valve is positioned in the highest point
of the hydraulic installation. Measurements indicate that the mathematical model can be used to
simulate this phenomenon by providing good accuracy.This work is supported by Fundacao para a Ciencia e Tecnologia (FCT), Portugal (grant number PD/BD/114459/2016).Coronado-Hernández, OE.; Besharat, M.; Fuertes-Miquel, VS.; Ramos, HM. (2019). Effect of a commercial air valve on the rapid filling of a single pipeline: a numerical and experimental analysis. Water. 11(9):1-13. https://doi.org/10.3390/w11091814S11311
A Semantic-Based Approach to Attain Reproducibility of Computational Environments in Scientic Work ows: A Case Study
Reproducible research in scientic work ows is often addressed by tracking the provenance of the produced results. While this approach allows inspecting intermediate and nal results, improves understanding, and permits replaying a work ow execution, it does not ensure that the computational environment is available for subsequent executions to reproduce the experiment. In this work, we propose describing the resources involved in the execution of an experiment using a set of semantic vocabularies, so as to conserve the computational environment. We dene a process for documenting the work ow application, management system, and their dependencies based on 4 domain ontologies. We then conduct an experimental evaluation sing a real work ow application on an academic and a public Cloud platform. Results show that our approach can reproduce an equivalent execution environment of a predened virtual machine image on both computing platforms
Forage production and bromatological composition of Gliricidia sepium (Jacq) Kunth ex Walp
Forage production and bromatologic composition of Gliricidia sepium (Jacq) Kunth ex Walp were evaluated on cattle raising serpentine soils from the Livestock Center Noel Fernández in Camagüey, Cuba. Data were processed by the statistical package SPSS, and mean and standard deviation were determined. G. sepium foliage levels were significant (3,68 kg/a/cut for green matter and 1,33 kg/a/cut for dry matter) and raw protein levels were satisfactory (13,2 %)
Evaluation of dead leaf and soil creatures associated to Gliricidia sepium (Jacq) Kunth ex Walp, used as live fences in savannahs
The contribution of decayed dry leaves and edaphic fauna to soil by using Gliricidia sepium (Jacq) Kunth ex Walp as living fences on savannas with a predominant serpentine stratum was determined in Camagüey municipality, Cuba. Results showed G. sepium beneficial environmental impact due to its high contribution of decayed dry leaves to soil, i.e., 332 kg/ha per month equivalent of 3,98 t/ha per year. Development of edaphic fauna earthworms and beetles mostly was enhanced, showing the benefits of this ecosystem environment, as well
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