280 resultados para Jacopo da


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BACKGROUND: In view of the obvious practical advantages, the most common test for hematuria is currently a reagent strip. METHODS: A standardized microscopic examination of the sediment was performed in 20 asymptomatic children referred for evaluation of chronic isolated microhematuria detected by means of a reagent strip. RESULTS: In 6 of the 20 children the microscopic examination failed to confirm the result of the dipstick test. CONCLUSIONS: Confirmation for the presence of hematuria by microscopy is the most important step in children with a positive dipstick for urinary blood.

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The occurrence and temporal variation of 18 perfluoroalkyl substances (PFASs) and 8 polybrominated diphenyl ethers (PBDEs) in the European Alps was investigated in a 10 m shallow firn core from Colle Gnifetti in the Monte Rosa Massif (4455 m above sea level). The firn core encompasses the years 1997-2007. Firn core sections were analyzed by liquid chromatography-tandem mass spectrometry (PFASs) and gas chromatography-mass spectrometry (PBDEs). We detected 12 PFASs and 8 PBDEs in the firn samples. Perfluorobutanoic acid (PFBA; 0.3-1.8 ng L(-1)) and perfluorooctanoic acid (PFOA; 0.2-0.6 ng L(-1)) were the major PFASs while BDE 99 (

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Spreading the PSF over a quite large amount of pixels is an increasingly used observing technique in order to reach extremely precise photometry, such as in the case of exoplanets searching and characterization via transits observations. A PSF top-hat profile helps to minimize the errors contribution due to the uncertainty on the knowledge of the detector flat field. This work has been carried out during the recent design study in the framework of the ESA small mission CHEOPS. Because of lack of perfect flat-fielding information, in the CHEOPS optics it is required to spread the light of a source into a well defined angular area, in a manner as uniform as possible. Furthermore this should be accomplished still retaining the features of a true focal plane onto the detector. In this way, for instance, the angular displacement on the focal plane is fully retained and in case of several stars in a field these look as separated as their distance is larger than the spreading size. An obvious way is to apply a defocus, while the presence of an intermediate pupil plane in the Back End Optics makes attractive to introduce here an optical device that is able to spread the light in a well defined manner, still retaining the direction of the chief ray hitting it. This can be accomplished through an holographic diffuser or through a lenslet array. Both techniques implement the concept of segmenting the pupil into several sub-zones where light is spread to a well defined angle. We present experimental results on how to deliver such PSF profile by mean of holographic diffuser and lenslet array. Both the devices are located in an intermediate pupil plane of a properly scaled laboratory setup mimicking the CHEOPS optical design configuration. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

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Because of physical processes ranging from microscopic particle collisions to macroscopic hydrodynamic fluctuations, any plasma in thermal equilibrium emits gravitational waves. For the largest wavelengths the emission rate is proportional to the shear viscosity of the plasma. In the Standard Model at 0T > 16 GeV, the shear viscosity is dominated by the most weakly interacting particles, right-handed leptons, and is relatively large. We estimate the order of magnitude of the corresponding spectrum of gravitational waves. Even though at small frequencies (corresponding to the sub-Hz range relevant for planned observatories such as eLISA) this background is tiny compared with that from non-equilibrium sources, the total energy carried by the high-frequency part of the spectrum is non-negligible if the production continues for a long time. We suggest that this may constrain (weakly) the highest temperature of the radiation epoch. Observing the high-frequency part directly sets a very ambitious goal for future generations of GHz-range detectors.

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The putative recent indication of an unidentified 3.55 keV X-ray line in certain astrophysical sources is taken as a motivation for an improved theoretical computation of the cosmological abundance of 7.1 keV sterile neutrinos. If the line is interpreted as resulting from the decay of Warm Dark Matter, the mass and mixing angle of the sterile neutrino are known. Our computation then permits for a determination of the lepton asymmetry that is needed for producing the correct abundance via the Shi-Fuller mechanism, as well as for an estimate of the non-equilibrium spectrum of the sterile neutrinos. The latter plays a role in structure formation simulations. Results are presented for different flavour structures of the neutrino Yukawa couplings and for different types of pre-existing lepton asymmetries, accounting properly for the charge neutrality of the plasma and incorporating approximately hadronic contributions.

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We present an overview of a perturbative-kinetic approach to jet propagation, energy loss, and momentum broadening in a high temperature quark–gluon plasma. The leading-order kinetic equations describe the interactions between energetic jet-particles and a non-abelian plasma, consisting of on-shell thermal excitations and soft gluonic fields. These interactions include ↔ scatterings, collinear bremsstrahlung, and drag and momentum diffusion. We show how the contribution from the soft gluonic fields can be factorized into a set of Wilson line correlators on the light-cone. We review recent field-theoretical developments, rooted in the causal properties of these correlators, which simplify the calculation of the appropriate Wilson lines in thermal field theory. With these simplifications lattice measurements of transverse momentum broadening have become possible, and the kinetic equations describing parton transport have been extended to next-to-leading order in the coupling g.

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Jacopo da Pontormo

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Apoptosis triggered by death receptors proceeds after defined signal-transduction pathways. Whether signaling at the receptor level is regulated by intracellular messengers is still unknown. We have investigated the role of two messengers, ceramide and nitric oxide (NO), on the apoptotic pathway activated in human monocytic U937 cells by tumor necrosis factor-α (TNF-α) working at its p55 receptor. Two transduction events, the receptor recruitment of the adapter protein, TRADD, and the activation of the initiator caspase, caspase 8, were investigated. When administered alone, neither of the messengers had any effect on these events. In combination with TNF-α, however, ceramide potentiated, whereas NO inhibited, TNF-α-induced TRADD recruitment and caspase 8 activity. The effect of NO, which was cGMP-dependent, was due to inhibition of the TNF-α-induced generation of ceramide. Our results identify a mechanism of regulation of a signal-transduction pathway activated by death receptors.

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Il tema della ricerca sono i caratteri della grafica a pastello in area italiana nel XVI secolo. Il lavoro è articolato in tre parti. Il primo capitolo analizza l’uso e il significato del termine “pastello” nelle fonti Cinque-Seicentesche. Il secondo capitolo ricostruisce il dibattito critico multidisciplinare sull’argomento. Se da una parte l’attenzione riservata al pastello da specialisti di diversi settori ha portato a una feconda varietà di punti di vista, dall’altro ha avuto come risultato una serie di ricostruzioni frammentarie. All’interno del dibattito sulla tecnica è stato possibile distinguere posizioni differenziate, in parte conseguenza dei diversi approcci e specializzazioni, ed enucleare alcuni nodi critici meritevoli di approfondimento. In primo luogo è possibile distinguere varie opinioni sulla fondamentale questione della natura e dei criteri di identificazione del medium, in particolare per i disegni risalenti al XVI secolo ovvero alla fase “embrionale” dell’utilizzo della tecnica. Si è proceduto poi, sulla base di queste premesse, all’analisi dei disegni del XVI secolo tradizionalmente ritenuti o recentemente proposti dalla storiografia come opere a pastello in ambito milanese, nelle aree settentrionali e centro-italiane. Successivamente è stato quindi studiato il ruolo della tecnica all’interno della grafica di Federico Barocci e Jacopo Bassano , i due artisti che si dedicano con maggiore intensità all’esplorazione delle possibilità del medium. Sono state infine considerate opere di artisti appartenenti alle generazioni successive (sempre entro il XVI secolo) che sperimentano l’uso dei pastelli policromi sul modello di Barocci e Bassano.

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This Policy Brief describes and discusses the proposals for a European Single Resolution Mechanism (SRM) for banks and for a Directive on Bank Recovery and Resolution (BRR). The authors find that the proposals are generally well designed and present a consistent approach, yet there is room for improvement, including the streamlining of procedures for the start of resolution, which now entail much overlap in the powers attributed to the various institutions involved (the Commission, the Single Resolution Board and the European Central Bank). The paper makes a number of key recommendations to facilitate discussions for stakeholders and regulators.

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This report assesses the energy costs borne by the steel industry in the EU between 2010 and 2012, and compares the energy costs, including both the energy components and other regulatory costs, to production costs, turnover and margins of steel-makers. The estimates of energy costs are based on primary sources, i.e. is on information provided by steel-makers through a written questionnaire. This information was validated by the research team by checking annual energy bills, when available, and other public sources. In this respect, this exercise represents a unique fact-based investigation into the costs of energy for steel-makers in Europe, whereas most of the information currently available in the public domain is based on secondary or statistical information. In 2012, the median EU steel plant pays about €33/MWh for gas, up from €26/MWh in 2010. As for electricity, in 2012 the EU median plant pays €62/MWh, up from €59/MWh in 2010. The report also includes a comparison with the prices of energy carriers paid by producers based in the US.