520 research outputs found

    Massive Star Cluster Formation and Destruction in Luminous Infrared Galaxies in GOALS

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    We present the results of a {\it Hubble Space Telescope} ACS/HRC FUV, ACS/WFC optical study into the cluster populations of a sample of 22 Luminous Infrared Galaxies in the Great Observatories All-Sky LIRG Survey. Through integrated broadband photometry we have derived ages and masses for a total of 484 star clusters contained within these systems. This allows us to examine the properties of star clusters found in the extreme environments of LIRGs relative to lower luminosity star-forming galaxies in the local Universe. We find that by adopting a Bruzual \& Charlot simple stellar population (SSP) model and Salpeter initial mass function, the age distribution of clusters declines as dN/dτ=τ−0.9+/−0.3dN/d\tau = \tau^{-0.9 +/- 0.3}, consistent with the age distribution derived for the Antennae Galaxies, and interpreted as evidence for rapid cluster disruption occuring in the strong tidal fields of merging galaxies. The large number of 106M⊙10^{6} M_{\odot} young clusters identified in the sample also suggests that LIRGs are capable of producing more high-mass clusters than what is observed to date in any lower luminosity star-forming galaxy in the local Universe. The observed cluster mass distribution of dN/dM=M−1.95+/−0.11dN/dM = M^{-1.95 +/- 0.11} is consistent with the canonical -2 power law used to describe the underlying initial cluster mass function (ICMF) for a wide range of galactic environments. We interpret this as evidence against mass-dependent cluster disruption, which would flatten the observed CMF relative to the underlying ICMF distribution.Comment: 63 pages, 58 Figures, 56 Tables, Accepted for publication in Ap

    The Mediterranean island states : Malta and Cyprus

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    The 2004 European Union enlargement also included the Mediterranean island-states of Cyprus and Malta, two former British colonies and members of the British Commonwealth. The islands share a number of similarities but they are also dissimilar in uniquely distinct ways. The membership applications of both states initially presented the EU with a number of political difficulties. With respect to Cyprus, many member states would have preferred to see the island join the Union after the ‘Cyprus Problem’ had been settled. As for Malta, the island showed a very high degree of Euroskepticism. It froze its application in 1996 but reactivated it in 1998. Apart from this skepticism the island’s neutral status, enshrined in the Constitution could present insurmountable problems.peer-reviewe

    Droplet minimizers for the Gates-Lebowitz-Penrose free energy functional

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    We study the structure of the constrained minimizers of the Gates-Lebowitz-Penrose free-energy functional FGLP(m){\mathcal F}_{\rm GLP}(m), non-local functional of a density field m(x)m(x), x∈TLx\in {\mathcal T}_L, a dd-dimensional torus of side length LL. At low temperatures, FGLP{\mathcal F}_{\rm GLP} is not convex, and has two distinct global minimizers, corresponding to two equilibrium states. Here we constrain the average density L^{-d}\int_{{\cal T}_L}m(x)\dd x to be a fixed value nn between the densities in the two equilibrium states, but close to the low density equilibrium value. In this case, a "droplet" of the high density phase may or may not form in a background of the low density phase, depending on the values nn and LL. We determine the critical density for droplet formation, and the nature of the droplet, as a function of nn and LL. The relation between the free energy and the large deviations functional for a particle model with long-range Kac potentials, proven in some cases, and expected to be true in general, then provides information on the structure of typical microscopic configurations of the Gibbs measure when the range of the Kac potential is large enough

    Ground state at high density

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    Weak limits as the density tends to infinity of classical ground states of integrable pair potentials are shown to minimize the mean-field energy functional. By studying the latter we derive global properties of high-density ground state configurations in bounded domains and in infinite space. Our main result is a theorem stating that for interactions having a strictly positive Fourier transform the distribution of particles tends to be uniform as the density increases, while high-density ground states show some pattern if the Fourier transform is partially negative. The latter confirms the conclusion of earlier studies by Vlasov (1945), Kirzhnits and Nepomnyashchii (1971), and Likos et al. (2007). Other results include the proof that there is no Bravais lattice among high-density ground states of interactions whose Fourier transform has a negative part and the potential diverges or has a cusp at zero. We also show that in the ground state configurations of the penetrable sphere model particles are superposed on the sites of a close-packed lattice.Comment: Note adde

    Deciphering the nuclear bile acid receptor FXR paradigm

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    Originally called retinoid X receptor interacting protein 14 (RIP14), the farnesoid X receptor (FXR) was renamed after the ability of its rat form to bind supra-physiological concentrations of farnesol. In 1999 FXR was de-orphanized since primary bile acids were identified as natural ligands. Strongly expressed in the liver and intestine, FXR has been shown to be the master transcriptional regulator of several entero-hepatic metabolic pathways with relevance to the pathophysiology of conditions such as cholestasis, fatty liver disease, cholesterol gallstone disease, intestinal inflammation and tumors. Furthermore, given the importance of FXR in the gut-liver axis feedbacks regulating lipid and glucose homeostasis, FXR modulation appears to have great input in diseases such as metabolic syndrome and diabetes. Exciting results from several cellular and animal models have provided the impetus to develop synthetic FXR ligands as novel pharmacological agents. Fourteen years from its discovery, FXR has gone from bench to bedside; a novel nuclear receptor ligand is going into clinical use

    Framing Cutting-Edge Integrative Deep-Sea Biodiversity Monitoring via Environmental DNA and Optoacoustic Augmented Infrastructures

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    Deep-sea ecosystems are reservoirs of biodiversity that are largely unexplored, but their exploration and biodiscovery are becoming a reality thanks to biotechnological advances (e.g., omics technologies) and their integration in an expanding network of marine infrastructures for the exploration of the seas, such as cabled observatories. While still in its infancy, the application of environmental DNA (eDNA) metabarcoding approaches is revolutionizing marine biodiversity monitoring capability. Indeed, the analysis of eDNA in conjunction with the collection of multidisciplinary optoacoustic and environmental data, can provide a more comprehensive monitoring of deep-sea biodiversity. Here, we describe the potential for acquiring eDNA as a core component for the expanding ecological monitoring capabilities through cabled observatories and their docked Internet Operated Vehicles (IOVs), such as crawlers. Furthermore, we provide a critical overview of four areas of development: (i) Integrating eDNA with optoacoustic imaging; (ii) Development of eDNA repositories and cross-linking with other biodiversity databases; (iii) Artificial Intelligence for eDNA analyses and integration with imaging data; and (iv) Benefits of eDNA augmented observatories for the conservation and sustainable management of deep-sea biodiversity. Finally, we discuss the technical limitations and recommendations for future eDNA monitoring of the deep-sea. It is hoped that this review will frame the future direction of an exciting journey of biodiscovery in remote and yet vulnerable areas of our planet, with the overall aim to understand deep-sea biodiversity and hence manage and protect vital marine resources

    IoTwins: Design and implementation of a platform for the management of digital twins in industrial scenarios

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    With the increase of the volume of data produced by IoT devices, there is a growing demand of applications capable of elaborating data anywhere along the IoT-to-Cloud path (Edge/Fog). In industrial environments, strict real-time constraints require computation to run as close to the data origin as possible (e.g., IoT Gateway or Edge nodes), whilst batch-wise tasks such as Big Data analytics and Machine Learning model training are advised to run on the Cloud, where computing resources are abundant. The H2020 IoTwins project leverages the digital twin concept to implement virtual representation of physical assets (e.g., machine parts, machines, production/control processes) and deliver a software platform that will help enterprises, and in particular SMEs, to build highly innovative, AI-based services that exploit the potential of IoT/Edge/Cloud computing paradigms. In this paper, we discuss the design principles of the IoTwins reference architecture, delving into technical details of its components and offered functionalities, and propose an exemplary software implementation

    Nuclear DNA from two early Neandertals reveals 80,000 years of genetic continuity in Europe

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    Little is known about the population history of Neandertals over the hundreds of thousands of years of their existence. We retrieved nuclear genomic sequences from two Neandertals, one from Hohlenstein-Stadel Cave in Germany and the other from Scladina Cave in Belgium, who lived around 120,000 years ago. Despite the deeply divergent mitochondrial lineage present in the former individual, both Neandertals are genetically closer to later Neandertals from Europe than to a roughly contemporaneous individual from Siberia. That the Hohlenstein-Stadel and Scladina individuals lived around the time of their most recent common ancestor with later Neandertals suggests that all later Neandertals trace at least part of their ancestry back to these early European Neandertals
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