Arc

Abstract A review of the chondrichthyan and osteichthyan fish fossils found in Japan is provided in the form of a series of tabular compilations covering the Late Mesozoic and Cenozoic Era. On the basis of this compilation, considerable changes are recognized in the fish faunas over a period of time. At the end of the Cretaceous Period a number of cartilaginous fishes disappeared. From the Oligocene to the Miocene, modern sharks including the family Carcharhinidae increased, whereas the Hexanchidae and Lamnidae declined. Most Miocene teleostean fishes differ from the Recent congeners at the species level.

The plasma spray process is widely used to produce thick coatings by the successive pilling of particles deposited in a molten or semi-molten state on a prepared substrate. However, this process includes time-dependent phenomena that affect the reliability of the process and reproducibility of coating. These phenomena are principally linked to the continuous movement of the electric arc root on the anode wall in the plasma gun. Such a movement leads to arc length variations resulting in fluctuations in arc voltage, enthalpy input to the flow and instabilities in the plasma jet. This paper presents an attempt to develop a time-dependent and 3-D model of the plasma spray process that can provide a useful insight in the time-evolution of the performance of the process. The effect of the transient behaviour of the arc on the gas flow is modelled with a time dependant heat source located inside the nozzle and evolving with the arc voltage. The first stage of the study consisted in the validation of the flow model thanks to the comparison of steady-state computed results with experimental data. The second dealt the time-dependant simulation of the flow.

Abstract: Drought is a hazardous and costly natural phenomenon with slow on-set that has dreadful impacts on economy, social life and environment of a country or region. The fact that it is slow on-set and is not quite distinguishable in when is it started or when ended makes the phenomena difficult to study (Hammouri and Naqa, 2007). Drought appears when rainfall in a region is less than statistical multi-year average for that region over an extended time period (Malaet al., 2014). It is a normal climatic event but its effect varies from region to region. There are four types of drought namely; meteorological drought, agricultural drought, hydrological drought and socio economic drought (Rathore, 2009). Meteorological drought is deficiency of rainfall which can be observed immediately (Panu andSharma, 2002). Although drought is a natural occurring recurrent extreme event (Wilhite, 1993; Shatanawi et al., 2013), various empirical and modelling studies proved that climate change is v...

Current practice in healthcare risk management is supported by many tools for risk assessment (understanding problems), but none for risk control (solving problems).  The results: a failure to improve safety, and a waste of the investment made in risk assessment.  The Active Risk Control (ARC) Toolkit, available for free, fills this void with a systematic, structured approach to risk control.

La spécialisation de plus en plus grande et le cloisonnement de nos domaines de recherche (histoire, histoire de l’art, archéologie...) conduisent le plus souvent à étudier et à publier séparément, malgré leur complémentarité, les sources épigraphiques et les sources iconographiques. Des salles de nos musées aux rayons de nos bibliothèques, documents sculptés et documents inscrits forment des ensembles "disjoints". Or, statuaire et épigraphie, signa et tituli, étaient dans l’Antiquité des éléments conçus ensemble, comme les deux volets d’un même message, indissociables dès la première formulation. Cette conjonction d’un texte et d’une image définit précisément le monumentum si caractéristique de la pratique commémorative romaine. Cet ouvrage, centré sur la question du monumentum romain, regroupe les communications présentées lors du colloque "Signa et tituli. Monuments et espaces de représentation en Gaule méridionale sous le regard croisé de la sculpture et de l’épig...

Il ciclo delle opere progettate da Guido Canella per la città di Bari occupa un arco temporale di oltre un decennio – dal 1991 al 2006 – e riguarda: il prototipo di Casa bifamiliare nel complesso residenzia- le di Barialto a Casamassima, del 1991; il progetto di Chiesa nello stesso complesso residenziale, del 1993; il progetto per i concorsi di primo e secondo grado per la Nuova sede municipale nell’area dell’ex gasometro, che si estende dal 1998 al 2001 e, infine, il progetto di Chiesa ecumenica, con Facoltà teologica, convento ortodosso e centro accoglienza a Punta Perotti, realizzato nell’ambito della decima Mostra Internazionale di Architettura di Venezia del 20061.
Lo definisco ciclo, perché tale deve essere considerato in quanto, nonostante la diversa collocazione temporale delle opere, le differenti tematiche affrontate e la diversità dei fattori contingenti di caratterizzazione di ciascuna esperienza progettuale, è innegabile il riconoscimento di un denominatore comune che lega, relazionandole, tutte e quattro le opere.
In tutti i casi assistiamo, infatti, alla volontà di interpretare i caratteri della grande civiltà architettonica del luogo mediante la traslitterazione dei significati e delle strutture sintattiche manifestate dai riferimenti adottati in forme ed espressioni del tempo presente. Ne sono scaturiti oggetti architettonici carichi di una straordinaria potenza evocativa, mondo di memoria, che riconquistano quella dimensione, spesso perduta, di perennità dell’architettura.

The Teloschistaceae is a widespread family with considerable morphological and ecological heterogeneity across genera and species groups. In order to provide a comprehensive molecular phylogeny for this family, phylogenetic analyses were carried out on sequences from the nuclear ribosomal ITS region obtained from 114 individuals that represent virtually all main lineages of Teloschistaceae. Our study confirmed the polyphyly of Caloplaca, Fulgensia and Xanthoria, and revealed that Teloschistes is probably non-monophyletic. We also confirm here that species traditionally included in Caloplaca subgenus Gasparrinia do not form a monophyletic entity. Caloplaca aurantia, C. carphinea and C. saxicola s. str. groups were recovered as monophyletic. The subgenera Caloplaca and Pyrenodesmia were also polyphyletic. In the subgenus Caloplaca, the traditionally recognized C. cerina group was recovered as monophyletic. Because this study is based solely on ITS, to maximize taxon sampling, the inclusion of phylogenetic signal from ambiguously aligned regions in MP (recoded INAASE and arc characters) resulted in the most highly supported phylogenetic reconstruction, compared with Bayesian inference restricted to alignable sites.

Long lasting forms of synaptic plasticity and long-term memory formation require new mRNA and protein synthesis. While activity-dependent expression of immediate-early genes has long been thought to account for such critical de novo macromolecular synthesis, experimental proof has been scarce until recently. During the past few decades, a growing number of genetic and molecular biological studies have started to elucidate

Entre le debut des annees 1960 et celui des annees 1990, l'architecture domestique de Sanaa a connu de profondes transformations. Cet article traite de l'evolution recente des elements architecturaux tels que la pierre, l'arc et le vitrail. En quelques decennies, a la faveur du developpement de la commande publique et de l'evolution des techniques de construction, ces elements constructifs sont devenus decoratifs. Ils constituent actuellement le vocabulaire d'une veritable yemenite architecturale largement diffusee.

Suez, Abou Simbel, Le Caire, Alger, Casablanca, Istanbul... Pour la première fois, des historiens de l'architecture et des conservateurs d'archives nous permettent d'accéder à un patrimoine culturel européen exceptionnel et méconnu : les archives produites par les entreprises du bâtiment et des travaux publics actives au sud de la Méditerranée, entre 1860 et 1970. Ouvrages d'art en acier ou béton armé, cités pour ouvriers et cadres expatriés, bâtiments publics mais aussi mobilier, décors, ouvrages effectués par des artisans d'art... Toutes ces réalisations témoignent d'une époque d'intenses échanges humains, techniques, et artistiques entre l'Europe et l'arc sud-est de la Méditerranée. Photographies anciennes destinées à promouvoir le travail des entrepreneurs, photographies de chantier, dessins d'architectes, croquis et carnets documentant les innovations techniques, plaquettes publicitaires... le livre est illustré par plus de 200 dessins et...

A mathematical model describing heat and fluid flow in an electric arc has been developed and used to predict heat transfer from the arc to the steel bath in a DC Electric Arc Furnace. The arc model takes the separate contributions to the heat transfer from each involved ...

A mathematical model describing heat and fluid flow in an electric arc has been developed and used to predict heat transfer from the arc to the steel bath in a DC Electric Arc Furnace. The arc model takes the separate contributions to the heat transfer from each involved ...

Concordant U–Pb zircon dates have been interpreted traditionally to date the crystallization ages of plutons because until recently analytical uncertainties have generally been large enough to encompass the anticipated duration of pluton growth. Advances in zircon TIMS analysis and geochronological studies by SIMS on zircon from young volcanic rocks, along with evolving views of the evolution of magmatic systems, makes it necessary to revaluate this interpretation. Assignment of unique pluton crystallization ages based on zircon dating is complicated by the propensity of zircon to survive multiple intrusive events that culminate in a large pluton. Distinctions must be made between true inherited zircon, xenocrystic zircon derived from host rocks during magma ascent and/or emplacement, and multi-stage growth of zircon during waxing and waning of magma reservoirs that solidify to form large plutons. These complications are exemplified by recent high-precision U–Pb zircon age dating from the Cretaceous Tuolumne and Mt. Stuart batholiths, which clearly show that the timeframe of pluton assembly was long (> 5 Ma for Mt. Stuart and > 8 Ma for Tuolumne). Zircon crystals from samples from both batholiths exhibit appreciable concordant age dispersion for zircon (several 105 yr up to 2 × 106 yr), and assignment of statistically valid rock solidification ages is not possible from these data. Low Zr in the rocks of each batholith indicates that magmas were initially strongly undersaturated in zircon when emplaced and inherited zircon is rare or absent. Recycling of zircon antecrysts during successive magmatic injections is the primary cause of the modest age dispersion of concordant zircon ages, and is compatible with progressive growth of a large, long-lived, crystal mush body. Because eruption of magma requires low to moderate crystal fraction and high temperatures (relative to stored crystal mushes), zircon crystals are more likely to be eradicated during thermal rejuvenation preceding major eruptions.

In contrast to their parent molecule cholesterol, two of its side-chain oxidized metabolites are able to cross the blood–brain barrier. There is a concentration-driven flux of 24S-hydroxycholesterol (24S-OHC) from the brain into the circulation, which is of major importance for elimination of excess cholesterol from the brain. The opposite flux of 27-hydroxycholesterol (27-OHC) from the circulation into the brain may regulate a number of key enzymes within the brain. In vitro experiments suggest that the balance between the levels of these two molecules may be of importance for the generation of β-amyloid peptides. In primary cultures of rat hippocampal cells 27-OHC is able to suppress expression of the activity regulated cytoskeleton-associated protein (Arc), a protein important in memory consolidation which is reduced in patients with Alzheimer’s disease (AD). In the present work we explore the possibility that the flux of 27-OHC from the circulation into the brain represents the missing link between AD and hypercholesterolemia, and discuss the possibility that modification of this flux may be a therapeutic strategy. Lastly, we discuss the use of oxysterols as diagnostic markers in neurodegenerative disease.