Fast Transition between High-soft and Low-soft States in GRS 1915+105: Evidence for a Critically Viscous Accretion Flow

We present the results of a detailed analysis of RXTE observations of class $\omega$ which show an unusual state transition between high-soft and low-soft states in the microquasar GRS 1915+105. Out of about 600 pointed RXTE observations, the source was found to exhibit such state transition only on 16 occasions. An examination of the RXTE/ASM data in conjunction with the pointed observations reveals that these events appeared as a series of quasi-regular dips in two stretches of long duration (about 20 days during each occasions) when hard X-ray and radio flux were very low. The X-ray light curve and color-color diagram of the source during these observations are found to be different from any reported so far. The duration of these dips is found to be of the order of a few tens of seconds with a repetition time of a few hundred seconds. The transition between these dips and non-dips which differ in intensity by a factor of ~ 3.5, is observed to be very fast (~ a few seconds). It is observed that the low-frequency narrow QPOs are absent in the power density spectrum (PDS) of the dip and non-dip regions of class $\omega$ and the PDS is a power law in 0.1 - 10 Hz frequency range. There is a remarkable similarity in the spectral and timing properties of the source during the dip and non-dip regions in these set of observations. These properties of the source are distinctly different from those seen in the observations of other classes. This indicates that the basic accretion disk structure during both dip and non-dip regions of class $\omega$ is similar, but differ only in intensity. To explain these observations, we invoke a model in which the viscosity is very close to critical viscosity and the shock wave is weak or absent.Comment: Replaced with correct figures, Jour. of Astrophysics and Astronomy (accepted

Subsolidus Phase Relations in Part of the System Si,Al,Y/N,O

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65882/1/j.1151-2916.1979.tb12762.x.pd

Contribución al estudio del "Pilling".

Los hilos una vez confeccionados en tejidos -de calada y de punto- presentan distintas aptitudes a la formación de «pilling». Una serie de ensayos nos permite establecer un sistema sencillo y práctico de determinar dicha aptitud. Fotográficamente se demuestra la formación del fenómeno de «pilling» y a través de un análisis microscópico de la bolita de «pilling» se estudia su composición y la forma de rotura de las fibras. Se desarrolla un método de valoración del «pilling» en función del peso de las bolitas producidas, estableciendo una correlación entre las normas existentes para la valoración del «pilling» y el peso de las bolitas desarrolladas.Yarns once converted in a fabric -woven or knitted- presenlt different aptitude to the formation of pilling. Through a series of tests we can establish a simple and practical system for determining the said aptitude. The phenomenon of the formation of pilling is demonstrated through photographs and its composition and the way the fibres break is studied by microscopical analysis. A new method of evaluating pilling as a function of the weight of the pilling produced, is developed and a possible correlation between the existing standards for pilling and this method is established.Les fils qui ont été confectionnés en tissus et tricots présentent différentes aptitudes au boulochage. Une série d'essais nous permet d'établir un systeme simple et pratique pour la détermination de cette aptitude. On démontre plhotographiquement la formation du phenomhne du «pilling» et moyennant une analyse microscopique de la bouloche du «pilling» on étudie sa composition ainsi que la forme de la rupture des fibres. On développe une méthode d'évaluation du «pilling» en fonction du poids des bouloches produites et on établit une correlation entre les normes existantes poul l'évaluation du «pilling» et le poids des bouloches développées.Peer Reviewe

Using a qubit to measure photon number statistics of a driven, thermal oscillator

We demonstrate theoretically how photon number statistics of a driven, damped oscillator at finite temperature can be extracted by measuring the dephasing spectrum of a two-level system dispersively coupled to the oscillator; we thus extend the work of Dykman (1987) and Gambetta et al. (2006). We carefully consider the fidelity of this scheme-- to what extent does the measurement reflect the initial number statistics of the mode? We also derive analytic results for the dephasing of a qubit by a driven, thermal mode, and compare results obtained at different levels of approximation. Our results have relevance both to experiments in circuit cavity QED, as well as to nano-electromechanical systems.Comment: 11 pages; 2 figures adde

Random access quantum information processors

Qubit connectivity is an important property of a quantum processor, with an ideal processor having random access -- the ability of arbitrary qubit pairs to interact directly. Here, we implement a random access superconducting quantum information processor, demonstrating universal operations on a nine-bit quantum memory, with a single transmon serving as the central processor. The quantum memory uses the eigenmodes of a linear array of coupled superconducting resonators. The memory bits are superpositions of vacuum and single-photon states, controlled by a single superconducting transmon coupled to the edge of the array. We selectively stimulate single-photon vacuum Rabi oscillations between the transmon and individual eigenmodes through parametric flux modulation of the transmon frequency, producing sidebands resonant with the modes. Utilizing these oscillations for state transfer, we perform a universal set of single- and two-qubit gates between arbitrary pairs of modes, using only the charge and flux bias of the transmon. Further, we prepare multimode entangled Bell and GHZ states of arbitrary modes. The fast and flexible control, achieved with efficient use of cryogenic resources and control electronics, in a scalable architecture compatible with state-of-the-art quantum memories is promising for quantum computation and simulation.Comment: 7 pages, 5 figures, supplementary information ancillary file, 21 page

On the origin of the various types of radio emission in GRS 1915+105

We investigate the association between the radio ``plateau'' states and the large superluminal flares in GRS 1915+105 and propose a qualitative scenario to explain this association. We identify several candidate superluminal flare events from available monitoring data on this source and analyze the contemporaneous RXTE pointed observations. We detect a strong correlation between the average X-ray flux during the ``plateau'' state and the total energy emitted in radio during the subsequent radio flare. We find that the sequence of events is similar for all large radio flares with a fast rise and exponential decay morphology. Based on these results, we propose a qualitative scenario in which the separating ejecta during the superluminal flares are observed due to the interaction of the matter blob ejected during the X-ray soft dips, with the steady jet already established during the ``plateau'' state. This picture can explain all types of radio emission observed from this source in terms of its X-ray emission characteristics.Comment: Corrected typo in the author names, contents unchanged, accepted in Ap

Estudio comparativo de la peinabilidad del cabello humano empleando distintos acondicionadores.

Un acondicionador es un agente químico que confiere al cabello dañado cierta elásticidad y peinabilidad independientemente de una mejor apariencia (brillo, etc.) suavidad y soltura. La eficacia objetiva de este tipo de cosméticos en cuanto a las propiedades tensiles puede verificarse por dinamometría. En este trabajo se determina la eficacia de cuatro acondicionadores comerciales distintos utilizando como criterio de evaluación la elasticidad, y carga para la rotura. Se mide también la peinabilidad empleando un dispositivo especial, en el dinamómetro que simula la operación de peinado. En conjunto se constata que los productos ensayados, confieren mayor elasticidad y resistencia al cabello. La peinabilidad tanto en seco como en húmedo mejora notablemente.Un conditionnateur est un agent chimique conférant aux cheveux nuis une certaine élasticité et une aptitude a la coiffure indépendamment d'un meilleur aspect (brillant, etc.) et d'une plus grande souplesse. L'efficacité objective de ce type de cosmétiques, quant aux propriétés tactiles, peut être vérifiée par dynamométrie. Dans ce travail, on détermine l'efficacité de quatre conditionnateurs commerciaux différents, en utilisant comme critere d'évaluation l'élasticité, et la charge a la rupture. On measure aussi l'aptitude a la coiffure en utilisant un dispositif spécial qui simule l'opération de coiffure dans le dynamometre. Dans l'ensemble, on constate que les produits essayés conferent une plus grande élasticité ainsi qu'une plus grande résistance aux cheveux. L'aptitude a la coiffure s'améliore notamment, a sec aussi bien qu'au mouillé.A hair conditioner is a chemical agent that confers to damaged hair some elasticity and combing ability, adding a befter look (sheen, soft, supple, etc). The objective eficiency of such type of cosmetics can be assessed by tensile testing. In this paper the eficiency of 4 comercial conditioners is evaluated by their elasticity and breaking load. The combing ability "combability" is also evaluated using a device adopted to tensile tester which simulates the combing operation. The 4 products tested show an improvement in hair elasticity, and resistance together with a better combability performance.Peer Reviewe

Substrate–Support Interactions Mediate Hydrogenation of Phenolic Compounds by Pd/CeO2 Nanorods

Ceria-supported palladium (Pd/CeO2) has spawned significant attention in recent years due to its ability to catalyze selective hydrogenation of phenolic compounds to cyclohexanones and cyclohexanols at a mild temperature and pressure. However, the mechanistic basis by which ceria enhances catalytic conversion is still unclear. Here, we use the increase in the 13C transverse relaxation rate upon the addition of nanoparticles (NPs) (13C ΔR2) to investigate the adsorption of phenolic compounds on the surface of the Pd/CeO2 catalyst by solution NMR. We show that hydroxyphenols adsorb on the support more efficiently than underivatized phenol and methoxyphenols and that phenol derivatives with an oxygen atom at position 2 (i.e., 2-hydroxyphenol and 2-methoxyphenol) form very stable interactions with the Pd site of Pd/CeO2. An analysis of the kinetics of hydrogenation revealed that catalytic conversion is linearly correlated with the ability of the substrate to form interactions with the CeO2 support and is inhibited by the formation of stable substrate–Pd adducts. Our data suggest that CeO2–substrate interactions mediate phenol hydrogenation more efficiently than Pd–substrate interactions and explain the exceptional catalytic performance reported for Pd/CeO2