556 research outputs found

    Mechanical behavior and durability of fibre reinforced mortar in an aggressive environment

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    International audienceThis study was carried out to examine the mechanical behavior and durability of mortar with or without addition of silica fume, with and without steel fibre reinforcement. Three tests were carried out: strength, depth of pH reduction and micro-structural analysis by SEM. The mixes studied had two water cement ratios (0.5; 0.65); with a 0.5% steel fibre content and 10% silica fume content (in substitution of cement). To characterize the durability performance of the mortars studied, samples were exposed to one-year in three environments: wet environment (control samples under laboratory conditions, 20°C and 95% RH) and exposure samples: in cyclic environment (wetting and drying) and a sewage pumping station sump (an aggressive environment). SEM observations were carried out on samples to study the micro structural changes in the mortar's matrix. One sees the organic matter deposits located inside a pore and one can see the formation of the secondary ettringite. It is concluded that the compressive strength of the samples are relatively unaffected by mix type and environment. The samples exposed to sewage exhibited evidence a depth of pH reduction

    Numerical study on Schramm-Loewner Evolution in nonminimal conformal field theories

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    The Schramm-Loewner evolution (SLE) is a powerful tool to describe fractal interfaces in 2D critical statistical systems. Yet the application of SLE is well established for statistical systems described by quantum field theories satisfying only conformal invariance, the so called minimal conformal field theories (CFTs). We consider interfaces in Z(N) spin models at their self-dual critical point for N=4 and N=5. These lattice models are described in the continuum limit by non-minimal CFTs where the role of a Z_N symmetry, in addition to the conformal one, should be taken into account. We provide numerical results on the fractal dimension of the interfaces which are SLE candidates for non-minimal CFTs. Our results are in excellent agreement with some recent theoretical predictions.Comment: 4 pages, 2 figures, v2: typos corrected, published versio

    Hubble Asteroid Hunter: II. Identifying strong gravitational lenses in HST images with crowdsourcing

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    The Hubble Space Telescope (HST) archives constitute a rich dataset of high resolution images to mine for strong gravitational lenses. While many HST programs specifically target strong lenses, they can also be present by coincidence in other HST observations. We aim to identify non-targeted strong gravitational lenses in almost two decades of images from the ESA it Hubble Space Telescope archive (eHST), without any prior selection on the lens properties. We used crowdsourcing on the Hubble Asteroid Hunter (HAH) citizen science project to identify strong lenses, alongside asteroid trails, in publicly available large field-of-view HST images. We visually inspected 2354 objects tagged by citizen scientists as strong lenses to clean the sample and identify the genuine lenses. We report the detection of 252 strong gravitational lens candidates, which were not the primary targets of the HST observations. 198 of them are new, not previously reported by other studies, consisting of 45 A grades, 74 B grades and 79 C grades. The majority are galaxy-galaxy configurations. The newly detected lenses are, on average, 1.3 magnitudes fainter than previous HST searches. This sample of strong lenses with high resolution HST imaging is ideal to follow-up with spectroscopy, for lens modelling and scientific analyses. This paper presents an unbiased search of lenses, which enabled us to find a high variety of lens configurations, including exotic lenses. We demonstrate the power of crowdsourcing in visually identifying strong lenses and the benefits of exploring large archival datasets. This study shows the potential of using crowdsourcing in combination with artificial intelligence for the detection and validation of strong lenses in future large-scale surveys such as ESA's future mission Euclid or in JWST archival images.Comment: 24 page, 14 figures, 5 tables, accepted for publication in A&A June 28 202

    Three-terminal resistive switch based on metal/metal oxide redox reactions

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    A solid-state three-terminal resistive switch based on gate-voltage-tunable reversible oxidation of a thin-film metallic channel is demonstrated. The switch is composed of a cobalt wire placed under a GdOx layer and a Au top electrode. The lateral resistance of the wire changes with the transition between cobalt and cobalt oxide controlled by a voltage applied to the top electrode. The kinetics of the oxidation and reduction process are examined through time- and temperature-dependent transport measurements. It is shown that that reversible voltage induced lateral resistance switching with a ratio of 10 3 can be achieved at room temperature. The reversible non-volatile redox reaction between metal and metal oxide may provide additional degrees of freedom for post-fabrication control of properties of solid-state materials. This type of three-terminal device has potential applications in neuromorphic computing and multilevel data storage, as well as applications that require controlling a relatively large current.National Science Foundation (U.S.) (Grant DMR-1419807

    THE AMPHIBIAN TREE OF LIFE

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    The evidentiary basis of the currently accepted classification of living amphibians is discussed and shown not to warrant the degree of authority conferred on it by use and tradition. A new taxonomy of living amphibians is proposed to correct the deficiencies of the old one. This new taxonomy is based on the largest phylogenetic analysis of living Amphibia so far accomplished. We combined the comparative anatomical character evidence of Haas (2003) with DNA sequences from the mitochondrial transcription unit H1 (12S and 16S ribosomal RNA and tRNAValine genes, ø 2,400 bp of mitochondrial sequences) and the nuclear genes histone H3, rhodopsin, tyrosinase, and seven in absentia, and the large ribosomal subunit 28S (ø 2,300 bp of nuclear sequences; ca. 1.8 million base pairs; x¯ 5 3.7 kb/terminal). The dataset includes 532 terminals sampled from 522 species representative of the global diversity of amphibians as well as seven of the closest living relatives of amphibians for outgroup comparisons. The primary purpose of our taxon sampling strategy was to provide strong tests of the monophyly of all ‘‘family-group’’ taxa. All currently recognized nominal families and subfamilies were sampled, with the exception of Protohynobiinae (Hynobiidae). Many of the currently recognized genera were also sampled. Although we discuss the monophyly of genera, and provide remedies for nonmonophyly where possible, we also make recommendations for future research. A parsimony analysis was performed under Direct Optimization, which simultaneously optimizes nucleotide homology (alignment) and tree costs, using the same set of assumptions throughout the analysis. Multiple search algorithms were run in the program POY over a period of seven months of computing time on the AMNH Parallel Computing Cluster. Results demonstrate that the following major taxonomic groups, as currently recognized, are nonmonophyletic: Ichthyophiidae (paraphyletic with respect to Uraeotyphlidae), Caeciliidae (paraphyletic with respect to Typhlonectidae and Scolecomorphidae), Salamandroidea (paraphyletic with respect to Sirenidae), Leiopelmatanura (paraphyletic with respect to Ascaphidae), Discoglossanura (paraphyletic with respect to Bombinatoridae), Mesobatrachia (paraphyletic with respect to Neobatrachia), Pipanura (paraphyletic with respect to Bombinatoridae and Discoglossidae/Alytidae), Hyloidea (in the sense of containing Heleophrynidae; paraphyletic with respect to Ranoidea), Leptodactylidae (polyphyletic, with Batrachophrynidae forming the sister taxon of Myobatrachidae 1 Limnodynastidae, and broadly paraphyletic with respect to Hemiphractinae, Rhinodermatidae, Hylidae, Allophrynidae, Centrolenidae, Brachycephalidae, Dendrobatidae, and Bufonidae), Microhylidae (polyphyletic, with Brevicipitinae being the sister taxon of Hemisotidae), Microhylinae (poly/paraphyletic with respect to the remaining non-brevicipitine microhylids), Hyperoliidae (para/polyphyletic, with Leptopelinae forming the sister taxon of Arthroleptidae 1 Astylosternidae), Astylosternidae (paraphyletic with respect to Arthroleptinae), Ranidae (paraphyletic with respect to Rhacophoridae and Mantellidae). In addition, many subsidiary taxa are demonstrated to be nonmonophyletic, such as (1) Eleutherodactylus with respect to Brachycephalus; (2) Rana (sensu Dubois, 1992), which is polyphyletic, with various elements falling far from each other on the tree; and (3) Bufo, with respect to several nominal bufonid genera. A new taxonomy of living amphibians is proposed, and the evidence for this is presented to promote further investigation and data acquisition bearing on the evolutionary history of amphibians. The taxonomy provided is consistent with the International Code of Zoological Nomenclature (ICZN, 1999). Salient features of the new taxonomy are (1) the three major groups of living amphibians, caecilians/Gymnophiona, salamanders/Caudata, and frogs/Anura, form a monophyletic group, to which we restrict the name Amphibia; (2) Gymnophiona forms the sister taxon of Batrachia (salamanders 1 frogs) and is composed of two groups, Rhinatrematidae and Stegokrotaphia; (3) Stegokrotaphia is composed of two families, Ichthyophiidae (including Uraeotyphlidae) and Caeciliidae (including Scolecomorphidae and Typhlonectidae, which are regarded as subfamilies); (4) Batrachia is a highly corroborated monophyletic group, composed of two taxa, Caudata (salamanders) and Anura (frogs); (5) Caudata is composed of two taxa, Cryptobranchoidei (Cryptobranchidae and Hynobiidae) and Diadectosalamandroidei new taxon (all other salamanders); (6) Diadectosalamandroidei is composed of two taxa, Hydatinosalamandroidei new taxon (composed of Perennibranchia and Treptobranchia new taxon) and Plethosalamandroidei new taxon; (7) Perennibranchia is composed of Proteidae and Sirenidae; (8) Treptobranchia new taxon is composed of two taxa, Ambystomatidae (including Dicamptodontidae) and Salamandridae; (9) Plethosalamandroidei new taxon is composed of Rhyacotritonidae and Xenosalamandroidei new taxon; (10) Xenosalamandroidei is composed of Plethodontidae and Amphiumidae; (11) Anura is monophyletic and composed of two clades, Leiopelmatidae (including Ascaphidae) and Lalagobatrachia new taxon (all other frogs); (12) Lalagobatrachia is composed of two clades, Xenoanura (Pipidae and Rhinophrynidae) and Sokolanura new taxon (all other lalagobatrachians); (13) Bombinatoridae and Alytidae (former Discoglossidae) are each others’ closest relatives and in a clade called Costata, which, excluding Leiopelmatidae and Xenoanura, forms the sister taxon of all other frogs, Acosmanura; (14) Acosmanura is composed of two clades, Anomocoela (5 Pelobatoidea of other authors) and Neobatrachia; (15) Anomocoela contains Pelobatoidea (Pelobatidae and Megophryidae) and Pelodytoidea (Pelodytidae and Scaphiopodidae), and forms the sister taxon of Neobatrachia, together forming Acosmanura; (16) Neobatrachia is composed of two clades, Heleophrynidae, and all other neobatrachians, Phthanobatrachia new taxon; (17) Phthanobatrachia is composed of two major units, Hyloides and Ranoides; (18) Hyloides comprises Sooglossidae (including Nasikabatrachidae) and Notogaeanura new taxon (the remaining hyloids); (19) Notogaeanura contains two taxa, Australobatrachia new taxon and Nobleobatrachia new taxon; (20) Australobatrachia is a clade composed of Batrachophrynidae and its sister taxon, Myobatrachoidea (Myobatrachidae and Limnodynastidae), which forms the sister taxon of all other hyloids, excluding sooglossids; (21) Nobleobatrachia new taxon, is dominated at its base by frogs of a treefrog morphotype, several with intercalary phalangeal cartilages—Hemiphractus (Hemiphractidae) forms the sister taxon of the remaining members of this group, here termed Meridianura new taxon; (22) Meridianura comprises Brachycephalidae (former Eleutherodactylinae 1 Brachycephalus) and Cladophrynia new taxon; (23) Cladophrynia is composed of two groups, Cryptobatrachidae (composed of Cryptobatrachus and Stefania, previously a fragment of the polyphyletic Hemiphractinae) and Tinctanura new taxon; (24) Tinctanura is composed of Amphignathodontidae (Gastrotheca and Flectonotus, another fragment of the polyphyletic Hemiphractinae) and Athesphatanura new taxon; (25) Athesphatanura is composed of Hylidae (Hylinae, Pelodryadinae, and Phyllomedusinae, and excluding former Hemiphractinae, whose inclusion would have rendered this taxon polyphyletic) and Leptodactyliformes new taxon; (26) Leptodactyliformes is composed of Diphyabatrachia new taxon (composed of Centrolenidae [including Allophryne] and Leptodactylidae, sensu stricto, including Leptodactylus and relatives) and Chthonobatrachia new taxon; (27) Chthonobatrachia is composed of a reformulated Ceratophryidae (which excludes such genera as Odontophrynus and Proceratophrys and includes other taxa, such as Telmatobius) and Hesticobatrachia new taxon; (28) Hesticobatrachia is composed of a reformulated Cycloramphidae (which includes Rhinoderma) and Agastorophrynia new taxon; (29) Agastorophrynia is composed of Bufonidae (which is partially revised) and Dendrobatoidea (Dendrobatidae and Thoropidae); (30) Ranoides new taxon forms the sister taxon of Hyloides and is composed of two major monophyletic components, Allodapanura new taxon (microhylids, hyperoliids, and allies) and Natatanura new taxon (ranids and allies); (31) Allodapanura is composed of Microhylidae (which is partially revised) and Afrobatrachia new taxon; (32) Afrobatrachia is composed of Xenosyneunitanura new taxon (the ‘‘strange-bedfellows’’ Brevicipitidae [formerly in Microhylidae] and Hemisotidae) and a more normal-looking group of frogs, Laurentobatrachia new taxon (Hyperoliidae and Arthroleptidae, which includes Leptopelinae and former Astylosternidae); (33) Natatanura new taxon is composed of two taxa, the African Ptychadenidae and the worldwide Victoranura new taxon; (34) Victoranura is composed of Ceratobatrachidae and Telmatobatrachia new taxon; (35) Telmatobatrachia is composed of Micrixalidae and a worldwide group of ranoids, Ametrobatrachia new taxon; (36) Ametrobatrachia is composed of Africanura new taxon and Saukrobatrachia new taxon; (37) Africanura is composed of two taxa: Phrynobatrachidae (Phrynobatrachus, including Dimorphognathus and Phrynodon as synonyms) and Pyxicephaloidea; (38) Pyxicephaloidea is composed of Petropedetidae (Conraua, Indirana, Arthroleptides, and Petropedetes), and Pyxicephalidae (including a number of African genera, e.g. Amietia [including Afrana], Arthroleptella, Pyxicephalus, Strongylopus, and Tomopterna); and (39) Saukrobatrachia new taxon is the sister taxon of Africanura and is composed of Dicroglossidae and Aglaioanura new taxon, which is, in turn, composed of Rhacophoroidea (Mantellidae and Rhacophoridae) and Ranoidea (Nyctibatrachidae and Ranidae, sensu stricto). Many generic revisions are made either to render a monophyletic taxonomy or to render a taxonomy that illuminates the problems in our understanding of phylogeny, so that future work will be made easier. These revisions are: (1) placement of Ixalotriton and Lineatriton (Caudata: Plethodontidae: Bolitoglossinae) into the synonymy of Pseudoeurycea, to render a monophyletic Pseudoeurycea; (2) placement of Haideotriton (Caudata: Plethodontidae: Spelerpinae) into the synonymy of Eurycea, to render a monophyletic Eurycea; (3) placement of Nesomantis (Anura: Sooglossidae) into the synonymy of Sooglossus, to assure a monophyletic Sooglossus; (4) placement of Cyclorana and Nyctimystes (Anura: Hylidae: Pelodryadinae) into Litoria, but retaining Cyclorana as a subgenus, to provide a monophyletic Litoria; (5) partition of ‘‘Limnodynastes’’ (Anura: Limnodynastidae) into Limnodynastes and Opisthodon to render monophyletic genera; (6) placement of Adenomera, Lithodytes, and Vanzolinius (Anura: Leptodactylidae) into Leptodactylus, to render a monophyletic Leptodactylus; (7) partition of ‘‘Eleutherodactylus’’ (Anura: Brachycephalidae) into Craugastor, ‘‘Eleutherodactylus’’, ‘‘Euhyas’’, ‘‘Pelorius’’, and Syrrhophus to outline the taxonomic issues relevant to the paraphyly of this nominal taxon to other nominal genera; (8) partition of ‘‘Bufo’’ (Anura: Bufonidae) into a number of new or revived genera (i.e., Amietophrynus new genus, Anaxyrus, Chaunus, Cranopsis, Duttaphrynus new genus, Epidalea, Ingerophrynus new genus, Nannophryne, Peltophryne, Phrynoidis, Poyntonophrynus new genus; Pseudepidalea new genus, Rhaebo, Rhinella, Vandijkophrynus new genus); (9) placement of the monotypic Spinophrynoides (Anura: Bufonidae) into the synonymy of (formerly monotypic) Altiphrynoides to make for a more informative taxonomy; (10) placement of the Bufo taitanus group and Stephopaedes (as a subgenus) into the synonymy of Mertensophryne (Anura: Bufonidae); (11) placement of Xenobatrachus (Anura: Microhylidae: Asterophryinae) into the synonymy of Xenorhina to render a monophyletic Xenorhina; (12) transfer of a number of species from Plethodontohyla to Rhombophryne (Microhylidae: Cophylinae) to render a monophyletic Plethodontohyla; (13) placement of Schoutedenella (Anura: Arthroleptidae) into the synonymy of Arthroleptis; (14) transfer of Dimorphognathus and Phrynodon (Anura: Phrynobatrachidae) into the synonymy of Phrynobatrachus to render a monophyletic Phrynobatrachus; (15) placement of Afrana into the synonymy of Amietia (Anura: Pyxicephalidae) to render a monophyletic taxon; (16) placement of Chaparana and Paa into the synonymy of Nanorana (Anura: Dicroglossidae) to render a monophyletic genus; (17) recognition as genera of Ombrana and Annandia (Anura: Dicroglossidae: Dicroglossinae) pending placement of them phylogenetically; (18) return of Phrynoglossus into the synonymy of Occidozyga to resolve the paraphyly of Phrynoglossus (Anura: Dicroglossidae: Occidozyginae); (19) recognition of Feihyla new genus for Philautus palpebralis to resolve the polyphyly of ‘‘Chirixalus’’; (20) synonymy of ‘‘Chirixalus’’ with Chiromantis to resolve the paraphyly of ‘‘Chirixalus’’; (21) recognition of the genus Babina, composed of the former subgenera of Rana, Babina and Nidirana (Anura: Ranidae); (22) recognition of the genera Clinotarsus, Humerana, Nasirana, Pelophylax, Pterorana, Pulchrana, and Sanguirana, formerly considered subgenera of Rana (Anura: Ranidae), with no special relationship to Rana (sensu stricto); (23) consideration of Glandirana (Anura: Ranidae), formerly a subgenus of Rana, as a genus, with Rugosa as a synonym; (24) recognition of Hydrophylax (Anura: Ranidae) as a genus, with Amnirana and most species of former Chalcorana included in this taxon as synonyms; (25) recognition of Hylarana (Anura: Ranidae) as a genus and its content redefined; (26) redelimitation of Huia to include as synonyms Eburana and Odorrana (both former subgenera of Rana); (27) recognition of Lithobates (Anura: Ranidae) for all species of North American ‘‘Rana’’ not placed in Rana sensu stricto (Aquarana, Pantherana, Sierrana, Trypheropsis, and Zweifelia considered synonyms of Lithobates); (28) redelimitation of the genus Rana as monophyletic by inclusion as synonyms Amerana, Aurorana, Pseudoamolops, and Pseudorana, and exclusion of all other former subgenera; (29) redelimitation of the genus Sylvirana (Anura: Ranidae), formerly a subgenus of Rana, with Papurana and Tylerana included as synonyms

    Off-diagonal correlations in one-dimensional anyonic models: A replica approach

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    We propose a generalization of the replica trick that allows to calculate the large distance asymptotic of off-diagonal correlation functions in anyonic models with a proper factorizable ground-state wave-function. We apply this new method to the exact determination of all the harmonic terms of the correlations of a gas of impenetrable anyons and to the Calogero Sutherland model. Our findings are checked against available analytic and numerical results.Comment: 19 pages, 5 figures, typos correcte

    RNAi phenotype profiling of kinases identifies potential therapeutic targets in Ewing's sarcoma

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    <p>Abstract</p> <p>Background</p> <p>Ewing's sarcomas are aggressive musculoskeletal tumors occurring most frequently in the long and flat bones as a solitary lesion mostly during the teen-age years of life. With current treatments, significant number of patients relapse and survival is poor for those with metastatic disease. As part of novel target discovery in Ewing's sarcoma, we applied RNAi mediated phenotypic profiling to identify kinase targets involved in growth and survival of Ewing's sarcoma cells.</p> <p>Results</p> <p>Four Ewing's sarcoma cell lines TC-32, TC-71, SK-ES-1 and RD-ES were tested in high throughput-RNAi screens using a siRNA library targeting 572 kinases. Knockdown of 25 siRNAs reduced the growth of all four Ewing's sarcoma cell lines in replicate screens. Of these, 16 siRNA were specific and reduced proliferation of Ewing's sarcoma cells as compared to normal fibroblasts. Secondary validation and preliminary mechanistic studies highlighted the kinases STK10 and TNK2 as having important roles in growth and survival of Ewing's sarcoma cells. Furthermore, knockdown of STK10 and TNK2 by siRNA showed increased apoptosis.</p> <p>Conclusion</p> <p>In summary, RNAi-based phenotypic profiling proved to be a powerful gene target discovery strategy, leading to successful identification and validation of STK10 and TNK2 as two novel potential therapeutic targets for Ewing's sarcoma.</p
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