4,304 research outputs found

    Posting of Workers Directive reloaded

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    In view of levelling the playing field between foreign and local employers in the host country, the European Commission proposed in March 2016 to revise the Posting of Workers Directive (PWD) 96/71/EC. The amended PWD (EU) 2018/957, that was adopted mid-2018, introduces some significant changes in order to combat the shortcomings resulting from the original PWD, strengthening the importance of ensuring fair competition (between local and foreign employers) and improving the protection of workers. In a nutshell, the PWD aims at promoting the principle of equal pay for equal work in the same place, especially by extending the so-called hard nucleus of working conditions and introducing a provision for long-term postings. This new legislation will be implemented throughout the EU as of mid-2020. The following article aims to investigate the extent to which the changes demand national implementation from an Austrian point-of-view; the latter could serve as a guidance

    Dune belt restoration effectiveness assessed by UAV topographic surveys (northern Adriatic coast, Italy)

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    Unoccupied aerial vehicle (UAV) monitoring surveys are used to assess a dune restoration project in the protected natural area of the Bevano River mouth on the northern Adriatic coast (Ravenna, Italy). The impacts of the installed fences to aid dune development are quantified in terms of sand volume and vegetation cover changes over 5 years using a systematic data processing workflow based on structure-from-motion (SfM) photogrammetry and the Geomorphic Change Detection (GCD) toolset applied to two drone surveys in 2016 and 2021. Accuracy assessment is performed using statistical analysis between ground-truth and model elevation data. Results show that the fence proves to be effective in promoting recovery and growth since significant sand deposition was observed along the dune foot and front – a total area of 3799 m2, volume of 1109 m3, and average depositional depth of 0.29 m. Progradation of around 3–5 m of the foredune and embryo development were also evident. There was a decrease in blowout features of about 155 m2 due to increased deposition and vegetation colonization. There was also an average percent increase of 160 % on wave-induced driftwood and/or debris along the beach and of 9.6 % vegetation within the fence based on the cover analysis on selected transects. Erosion of around 1439 m2 is apparent mostly at the northern portion of the structure, which could be accounted for by the aerodynamic and morphodynamic conditions around the fence and its configuration to trap sediments and efficiency in doing so. Overall, dune fencing coupled with limiting debris cleaning along the protected coast was effective. The proposed workflow can aid in creating transferable guidelines to stakeholders in integrated coastal zone management (ICZM) implementation on Mediterranean low-lying sandy coasts

    Higher-Derivative Corrections and AdS5_5 Black Holes

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    Using recent results in four-derivative 5d N=2\mathcal{N}=2 minimal gauged supergravity, we evaluate the regularized on-shell action of the Euclidean solution in this theory that admits a Lorentzian continuation to an AdS5_5 black hole with one electric charge and two angular momenta. We focus on the supersymmetric limit of this solution and employ holography to show that the result can be expressed purely in terms of angular momentum fugacities and the 't Hooft anomalies for the U(1)R\mathrm{U}(1)_{\mathrm R} R-symmetry of the dual 4d N=1\mathcal{N}=1 SCFT. This holographic calculation is in perfect agreement with recent studies of the 4d N=1\mathcal{N}=1 superconformal index ``on the second sheet''. We illustrate the utility of these results in two classes of 4d N=1\mathcal{N}=1 holographic SCFTs that have 't Hooft anomalies with suitable large NN behavior that leads to non-trivial corrections at first subleading order in the 1/N1/N expansion. We also explicitly calculate the Wald entropy of the black hole solution and delineate the leading four-derivative corrections to the Bekenstein-Hawking entropy.Comment: 7 pages, higher-derivative computations done with the Mathematica package available at https://github.com/waskou/SolutionsX; v2: corrections and comments added concerning the entropy formula, ancillary files available at https://github.com/waskou/Solutions

    Computational and experimental studies of selected magnesium and ferrous sulfate hydrates: implications for the characterisation of extreme and extraterrestrial environments

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    Magnesium sulfate hydrates are considered important rock-forming minerals on the outer three Galilean moons of Jupiter (i.e., Europa, Ganymede, Callisto) and, alongside ferrous sulfate hydrates, are promising candidate minerals for the widespread sulfate deposits that occur in the equatorial region of Mars. In such extraterrestrial environments, these minerals experience extreme high-pressure conditions in the interiour of the Galilean moons and low temperature conditions on the surface of these moons and Mars. The aim of this thesis is to understand the structural stability, compressibility, and thermal expansion of these compounds in such extreme environments and aid their identification in ongoing and future space missions. Most magnesium sulfate hydrates lack accurate reference elastic tensors, which hinders their seismological identification in lander missions on the icy moons of the outer solar system, as envisioned for the near future. In this thesis, the accuracy of recent advancements in density functional theory to predict the compressibility and elastic constants of icy satellite candidate minerals (i.e., epsomite (MgSO₄·7H₂O), gypsum (CaSO₄·2H₂O), carbon dioxide (CO₂), and benzene (C₆H₆)) was assessed by benchmarking them against experimental reference data from the literature. Key findings are that density functional theory calculations do not yield elastic constants accurate enough to be used as a reference for the seismic exploration of icy moons. However, the bulk compressibility of such materials is very accurately reproduced by density functional theory, which was therefore used to predict the compressibility of the icy satellite candidate minerals starkeyite (MgSO₄·4H₂O) and cranswickite (MgSO₄·4H₂O). Knowledge of the compressibility of such minerals is critical to model mantle processes (e.g., salt diaprisim, plate tectonics, subduction) and the density structure of the outer three Galilean moons. The thermal expansion and structural stability of three sulfate minerals (i.e., rozenite (FeSO₄·4H₂O), starkeyite, and cranswickite) was characterised for the first time using neutron diffraction. Cranswickite transforms to starkeyite at 330 K, well above the maximum surface temperature of 308 K hitherto reported on Mars. Starkeyite likely undergoes a structural phase transition at around 245 K. The structure of this proposed low-temperature polymorph could not be determined but would be of great interest since the temperature drops below 245 K on equatorial Mars at night-time. Starkeyite was also studied by means of synchrotron X-ray diffraction but suffered radiation damage. No phase transition was observed in rozenite from 290 – 21 K, which contrasts with Raman data reported in the literature, where sharpening of vibrational modes upon cooling was misinterpreted as mode splitting and evidence for two phase transitions at temperatures relevant to the Martian surface. First-principles phonon frequency calculations provide evidence supporting the absence of vibrational mode splitting. A workflow to obtain reliable reference Raman spectra for space exploration was proposed and an optical centre stick for the simultaneous acquisition of neutron diffraction and Raman spectroscopy data at the HRPD instrument was commissioned. Lastly, the structure of a polymorph of hexahydrite (MgSO₄·6H₂O), most recently proposed in the literature, was shown to be unambiguously wrong

    Near-future discovery of the diffuse flux of ultra-high-energy cosmic neutrinos

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    Ultra-high-energy (UHE) neutrinos, with EeV-scale energies, carry with them unique insight into fundamental open questions in astrophysics and particle physics. For fifty years, they have evaded discovery, but maybe not for much longer, thanks to new UHE neutrino telescopes, presently under development. We capitalize on this upcoming opportunity by producing state-of-the-art forecasts of the discovery of a diffuse flux of UHE neutrinos in the next 10-20 years. By design, our forecasts are anchored in often-overlooked nuance from theory and experiment; we gear them to the radio array of the planned IceCube-Gen2 detector. We find encouraging prospects: even under conservative analysis choices, most benchmark UHE neutrino flux models available in the literature may be discovered within 10 years of detector exposure -- many sooner -- and may be distinguished from each other. Our results validate the transformative potential of next-generation UHE neutrino telescopes.Comment: 31 pages, 22 figures, 3 tables, plus appendix and reference

    Ecoenzymatic stoichiometry as a temporally integrated indicator of nutrient availability in soils

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    The extent to which soil enzyme activity in assessing soil nutrient availability is useful has been controversial. In this review, we discuss the utility of ecoenzymatic stoichiometry (i.e. the ratio of nutrient- to carbon (C)-acquiring enzyme activities) on the basis of the resource allocation model for ecoenzyme synthesis. Both the selection of appropriate enzymes and the balance between relative amounts of substrates and enzymes in the soil are decisive factors in utilizing the ecoenzymatic stoichiometry. Ecoenzymatic stoichiometry can evaluate the availability of nitrogen (N), phosphorus, and sulfur in many soils in which the enzyme catalytic reactions are substrate-limited but not enzyme-limited. However, the ecoenzymatic stoichiometry approach does not seem to be applicable in soils where microbes are limited by factors other than nutrient availability, such as low temperature, where the enzyme catalytic reactions are enzyme-limited. Certain enzymes, such as N-acetyl-β-glucosaminidase and protease, appear to be insensitive to soil N availability, because they release compounds containing both N and C which serve as sources for both N and C/energy. We propose the use of enzymes such as L-asparaginase and urease as N-acquiring enzymes that release a compound containing N but not C (i.e. NH4+) as the hydrolysis product. Ecoenzymatic stoichiometry can be considered as an indicator of long-term (weeks) temporally integrated soil nutrient availability, rather than instantaneous availability, for plants as well as microbes, because of (i) the long-term persistence of extracellular enzymes in soils; (ii) a significant correlation between ecoenzymatic stoichiometry and the measurements reflecting the quantity of long-term available nutrients in soil; and (iii) a significant correlation between ecoenzymatic stoichiometry and plant nutrient uptake. This review also identifies challenges in assessing microbial nutrient limitation using ecoenzymatic stoichiometry. With a comprehensive understanding of underlying mechanisms and limitations, ecoenzymatic stoichiometry can be used as a biologically relevant indicator of nutrient availability in combination with other approaches such as conventional chemical extraction methods and the nutrient addition approach.Ecoenzymatic stoichiometry as a temporally integrated indicator of nutrient availability in soils. Soil Science and Plant Nutrition, 70(4), 246–269. (2024)journal articl

    ÂżZĂłsimo de PanĂłpolis fue cristiano?

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    Zosimus of Panopolis, the first identifiable author of Greek alchemy, wrote in late-3rd or 4th-century CE Egypt. For over a century, scholars have pictured him in turn as Christian or as pagan. A reconsideration of Zosimus’ On the Letter Omega and the treatise known as the Final Count or Final Abstinence (teleutaia apochē) and the First Lesson on Excellence demonstrates that he saw Jesus as a savior, that his citations of the Hermetica are not in contradiction with basic Christian notions and that believed that the gods of Egypt were evil divine beings. His Christology and anthropology shares characteristics with “Classic Gnostic” theology and other early Christian notions. Also characteristic of the soteriologies presented in some heresiological reports, Zosimus described Jesus as teaching humans to “cut off” their body. This last observation, which is dependent on recognizing Zosimus as a Christian, shed light on the symbolism of the First Lesson on Excellence.Zósimo de Panópolis, el primer autor identificable de alquimia griega, escribió en Egipto a finales del siglo III o IV E.C. Durante más de un siglo, los eruditos lo han considerado alternativamente como cristiano o como pagano. Una reconsideración de su tratado Sobre la letra Omega y el tratado conocido como La cuenta final o La abstinencia final (teleutaia apochē) y la Primera lección sobre la excelencia demuestra que percibió a Jesús como un salvador, que sus citas de las Hermetica no están en contradicción con nociones cristianas básicas y que creía que los dioses de Egipto eran seres divinos malvados. Su cristología y antropología comparten características con la teología “gnóstica clásica” y otras nociones cristianas primitivas. También es característico de las soteriologías presentadas en algunos informes heresiológicos, en los que Zósimo describió a Jesús enseñando a los humanos a “cortar” su cuerpo. Esta última observación, que depende de que se reconozca a Zósimo como cristiano, arroja luz sobre el simbolismo de la Primera lección sobre la excelencia
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