829 research outputs found

    J0811+4730: the most metal-poor star-forming dwarf galaxy known

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    We report the discovery of the most metal-poor dwarf star-forming galaxy (SFG) known to date, J0811+4730. This galaxy, at a redshift z=0.04444, has a Sloan Digital Sky Survey (SDSS) g-band absolute magnitude M_g = -15.41 mag. It was selected by inspecting the spectroscopic data base in the Data Release 13 (DR13) of the SDSS. LBT/MODS spectroscopic observations reveal its oxygen abundance to be 12 + log O/H = 6.98 +/- 0.02, the lowest ever observed for a SFG. J0811+4730 strongly deviates from the main-sequence defined by SFGs in the emission-line diagnostic diagrams and the metallicity - luminosity diagram. These differences are caused mainly by the extremely low oxygen abundance in J0811++4730, which is ~10 times lower than that in main-sequence SFGs with similar luminosities. By fitting the spectral energy distributions of the SDSS and LBT spectra, we derive a stellar mass of M* = 10^6.24 - 10^6.29 Msun (statistical uncertainties only), and we find that a considerable fraction of the galaxy stellar mass was formed during the most recent burst of star formation.Comment: 12 pages, 5 figures, accepted for publication in MNRA

    SBS 0335-052W: The Lowest-Metallicity Star-Forming Galaxy Known

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    We present 4-meter Kitt Peak telescope and 6.5-meter MMT spectrophotometry of the extremely low-metallicity galaxy SBS 0335-052W, the western companion of the blue compact dwarf galaxy SBS 0335-052E. These observations have been combined with published 10-meter Keck data to derive for the brightest region of SBS 0335-052W an oxygen abundance 12+logO/H=7.12+/-0.03. This makes SBS 0335-052W the lowest metallicity star-forming galaxy known in the local universe. Using a Monte Carlo technique, we fit the spectral energy distribution of SBS 0335-052W to derive the age of the oldest stars contributing to its optical light. We find that star formation in SBS 0335-052W began less than 500 Myr ago, making it a likely nearby young dwarf galaxy.Comment: 13 pages, 3 figures, accepted for publication in the Astrophysical Journa

    Extending the turbulent length scale equation with the use of LES data

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    The k − kL closure model naturally occurring higher derivative terms, and due to its nature provides a good starting point for studying effects of inflectional instabilities in wakes. In this work, results of scale resolving simulations of a turbulent boundary layer and its corresponding wake at adverse pressure gradients are evaluated with the aim of establishing physics based bounds and assumptions for the expansion of turbulent length scale equations to improve RANS predictive capability for adverse pressure gradients

    Investigation of the thermophysical properties of high-melting materials with the aid of a complex of instruments

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    The evaporation rate, vapor pressure, heats of evaporation reaction (sublimation, dissociation), enthalpy, electrical resistance, heat capacity, emissivity, and heat conductivity of various carbides, borides, sulfides, nitrides, selenides, and phosphides were investigated. A set of high temperature high vacuum devices, calorimeters (designed for operation at 400 to 1300 K and from 1200 K), and mass spectrometers, most of which were specially developed for these studies, is described

    Moral distress measurement in animal care workers: a systematic review.

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    The mental health of veterinary and other animal health professionals is significantly impacted by the psychological stressors they encounter, such as euthanasia, witnessing animal suffering and moral distress. Moral distress, initially identified in nursing, arises when individuals are aware of the right action but are hindered by institutional constraints. We aimed to review existing research on moral distress scales among animal care workers by focusing on the identification and psychometric validity of its measurement. Two-step systematic review. First, we identified all moral distress scales used in animal care research in the eligible original studies. Second, we evaluated their psychometric validity, emphasising content validity, which is a critical aspect of patient-reported outcome measures (PROMs). This evaluation adhered to the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN). The results were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. PubMed, EMBASE and PsycINFO to search for eligible studies published between January 1984 and April 2023. We included original (primary) studies that (1) were conducted in animal care workers; (2) describing either the development of a moral distress scale, or validation of a moral distress scale in its original or modified version, to assess at least one of the psychometric properties mentioned in COSMIN guidelines. Two independent reviewers used standardised methods to search, screen and code included studies. We considered the following information relevant for extraction: study reference, name and reference of the moral distress scale used, psychometric properties assessed and methods and results of their assessments. The collected information was then summarised in a narrative synthesis. The review identified only one PROM specifically adapted for veterinary contexts: the Measure of Moral Distress for Animal Professionals (MMD-AP), derived from the Measure of Moral Distress for Healthcare Professionals (MMD-HP). Both MMD-HP and MMD-AP were evaluated for the quality of development and content validity. The development quality of both measures was deemed doubtful. According to COSMIN, MMD-HP's content validity was rated as sufficient, whereas MMD-AP's was inconsistent. However, the evidence quality for both PROMs was rated low. This is the first systematic review focused on moral distress measurement in animal care workers. It shows that moral distress is rarely measured using standardised and evidence-based methods and that such methods should be developed and validated in the context of animal care. CRD42023422259

    Solución innovadora que utiliza tecnología iónica-electrónica para purificar el aire de la microflora patógena y crear condiciones de vida confortables para las personas.

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    Según los datos del Servicio Federal de Estadística del Estado sobre enfermedades respiratorias en el territorio de Krasnoyarsk, el aumento de este indicador fue del 6% en los últimos cinco años, y el aumento de las enfermedades oncológicas fue del 4% en el mismo período. El aire contaminado es una de las principales causas del aumento de la incidencia. El objetivo del trabajo es encontrar formas de limpiar el aire interior mediante tecnología iónica-electrónica y llevar los parámetros del microclima a valores óptimos en las estaciones frías y cálidas. Los estudios experimentales y teóricos corroboraron la posibilidad de desarrollar un dispositivo capaz de crear y mantener un ambiente de aire en espacios cerrados, cercano en términos de indicadores al aire saludable de las regiones ecológicamente limpias. El dispositivo puede tener diferentes características y puede utilizarse en locales domésticos, industriales y públicos. Dependiendo del modo de funcionamiento y el propósito, este dispositivo puede ser tanto estacionario como móvil. El polvo fino no se puede eliminar de la habitación incluso si la tasa de intercambio de aire se incrementa entre 200 y 400 veces. Se ha demostrado experimentalmente que la tecnología iónica-electrónica y la materia volátil de las plantas leñosas eliminan el polvo para lograr una sala limpia . Este concepto sirvió de base para el desarrollo de un dispositivo que utiliza nanotecnología combinada con materia volátil de plantas leñosas. La dependencia de la influencia de la ionización artificial del aire y de la materia volátil de plantas leñosas en la reducción de la cantidad de polvo fino y de microflora patógena está comprobada teóricamente. El aire purificado de esta manera mantiene la inmunidad y reduce la incidencia de enfermedades respiratorias, lo que se ha demostrado experimentalmente sobre la base de un prototipo del dispositivo desarrollado

    Strategies and innovations in modern trade marketing

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    Purpose: The article is devoted to the critical analysis of existing theoretical and methodological approaches to determining the content and nature of sales marketing as a factor and element of companies’ competitive strategy. Design/Methodology/Approach: Based on a critical retrospective analysis, authors presented the features of the trade marketing toolkit providing substantial increase in market sales. Authors considered key existing functional marketing strategies, as well as its innovative trends and ideas. Findings: The modern market of trade enterprises is characterized by fundamental changes in economic conditions caused by the transformation of the economic system, the market priority of consumers, the formation of the information society, and the integration of economic processes. The economic phenomena escalate the struggle in the trading business for its share of the competitive market. In order to maintain and strengthen their positions, trade enterprises should build their trade and technological processes more and more efficiently. Practical implications: Economic growth of a commercial enterprise could be carried out in line with intensive and extensive factors. With the growing level of concentration of the trade industry, factors of intensive economic growth of trade enterprises become relevant. Originality/Value: The author's approach could be used in the development of promising corporate marketing strategies in terms of the development and implementation of innovative marketing solutions available for implementation throughout the entire cycle of the strategic marketing process.peer-reviewe
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