Superconductivity-Induced Transfer of In-Plane Spectral Weight in Bi2Sr2CaCu2O8: Resolving a Controversy

We present a detailed analysis of the superconductivity-induced redistribution of optical spectral weight in Bi2Sr2CaCu2O8 near optimal doping. It confirms the previous conclusion by Molegraaf et al. (Science 66, 2239 (2002)), that the integrated low-frequency spectral weight shows an extra increase below Tc. Since the region, where the change of the integrated spectral weight is not compensated, extends well above 2.5 eV, this transfer is caused by the transfer of spectral weight from interband to intraband region and only partially by the narrowing of the intraband peak. We show that the opposite assertion by Boris et al. (Science 304, 708 (2004)) regarding this compound, is unlikely the consequence of any obvious discrepancies between the actual experimental data.Comment: ReVTeX, 9 pages, 8 encapsulated postscript figures, several typo's correcte

Different effects of Ni and Co substitution on the transport properties of BaFe2As2

We report resistivity and Hall effect results on Ba(Fe1-xNix)2As2 and compare them with those in Ba(Fe1-xCox)2As2. The Hall number RH is negative for all x values from 0.01 to 0.14, which indicates that electron carriers dominate the transport both in the magnetic and paramagnetic regime. We analyse the data in the framework of a two-band model. Without any assumption on the number of carriers, we show that the electron resistivity can be estimated with good accuracy in the low temperature paramagnetic range. Although the phase diagrams of the two families are very similar with respect to the extra electrons added in the system, we find that the transport properties differ in several aspects. First, we evidence that the contribution of holes to the transport is more important for Ni doping than for Co doping. Secondly, Ni behaves as a stronger scatterer for the electrons, as the increase of the residual electron resistivity rho/x is about four times larger for Ni than for Co in the most doped samples.Comment: 8 pages, 8 figure

Symptom complexes in patients with seropositive arthralgia and in patients newly diagnosed with rheumatoid arthritis: a qualitative exploration of symptom development

Objective: The aim of this study was to explore symptoms and symptom development during the earliest phases of rheumatoid arthritis (RA) in patients with seropositive arthralgia and patients newly diagnosed with RA

Sudden Collapse of a Granular Cluster

Single clusters in a vibro-fluidized granular gas in N connected compartments become unstable at strong shaking. They are experimentally shown to collapse very abruptly. The observed cluster lifetime (as a function of the driving intensity) is analytically calculated within a flux model, making use of the self-similarity of the process. After collapse, the cluster diffuses out into the uniform distribution in a self-similar way, with an anomalous diffusion exponent 1/3.Comment: 4 pages, 4 figures. Figure quality has been reduced in order to decrease file-siz

Discovery of distant high luminosity infrared galaxies

We have developed a method for selecting the most luminous galaxies detected by IRAS based on their extreme values of R, the ratio of 60 micron and B-band luminosity. These objects have optical counterparts that are close to or below the limits of Schmidt surveys. We have tested our method on a 1079 deg^2 region of sky, where we have selected a sample of IRAS sources with 60 micron flux densities greater than 0.2 Jy, corresponding to a redshift limit z~1 for objects with far-IR luminosities of 10^{13} L_sun. Optical identifications for these were obtained from the UK Schmidt Telescope plates, using the likelihood ratio method. Optical spectroscopy has been carried out to reliably identify and measure the redshifts of six objects with very faint optical counterparts, which are the only objects with R>100 in the sample. One object is a hyperluminous infrared galaxy (HyLIG) at z=0.834. Of the remaining, fainter objects, five are ultraluminous infrared galaxies (ULIGs) with a mean redshift of 0.45, higher than the highest known redshift of any non-hyperluminous ULIG prior to this study. High excitation lines reveal the presence of an active nucleus in the HyLIG, just as in the other known infrared-selected HyLIGs. In contrast, no high excitation lines are found in the non-hyperluminous ULIGs. We discuss the implications of our results for the number density of HyLIGs at z<1 and for the evolution of the infrared galaxy population out to this redshift, and show that substantial evolution is indicated. Our selection method is robust against the presence of gravitational lensing if the optical and infrared magnification factors are similar, and we suggest a way of using it to select candidate gravitationally lensed infrared galaxies.Comment: 6 pages, accepted for publication in A&

Digital Creativity Support for Original Journalism

The decline in circulations and revenues resulting from the digitalization of news production and consumption has led to a crisis in journalism.Journalists have less time to research, investigate and write original stories, leading to problems for our democratic processes and holding the powerful to account. This paper reports the architecture, features and rationale for new digital creativity support designed to support journalists to discover more original angles onstories. It also summarises the evaluation of the tool’s use in 3 newsrooms

Effect of long-range Coulomb interaction on shot-noise suppression in ballistic transport

We present a microscopic analysis of shot-noise suppression due to long-range Coulomb interaction in semiconductor devices under ballistic transport conditions. An ensemble Monte Carlo simulator self-consistently coupled with a Poisson solver is used for the calculations. A wide range of injection-rate densities leading to different degrees of suppression is investigated. A sharp tendency of noise suppression at increasing injection densities is found to scale with a dimensionless Debye length related to the importance of space-charge effects in the structure.Comment: RevTex, 4 pages, 4 figures, minor correction

Nonadiabatic Electron Manipulation in Quantum-Dot Arrays

A novel method of coherent manipulation of the electron tunneling in quantum-dots is proposed, which utilizes the quantum interference in nonadiabatic double-crossing of the discrete energy levels. In this method, we need only a smoothly varying gate voltage to manipulate electrons, without a sudden switching-on and off. A systematic design of a smooth gate-pulse is presented with a simple analytic formula to drive the two-level electronic state to essentially arbitrary target state, and numerical simulations for complete transfer of an electron is shown for a coupled double quantum-dots and an array of quantum-dots. Estimation of the manipulation-time shows that the present method can be employed in realistic quantum-dots

The Mass-to-Light Ratio of Binary Galaxies

We report on the mass-to-light ratio determination based on a newly selected binary galaxy sample, which includes a large number of pairs whose separations exceed a few hundred kpc. The probability distributions of the projected separation and the velocity difference have been calculated considering the contamination of optical pairs, and the mass-to-light ratio has been determined based on the maximum likelihood method. The best estimate of $M/L$ in the B band for 57 pairs is found to be 28 $\sim$ 36 depending on the orbital parameters and the distribution of optical pairs (solar unit, $H_0=50$ km s$^{-1}$ Mpc$^{-1}$). The best estimate of $M/L$ for 30 pure spiral pairs is found to be 12 $\sim$ 16. These results are relatively smaller than those obtained in previous studies, but consistent with each other within the errors. Although the number of pairs with large separation is significantly increased compared to previous samples, $M/L$ does not show any tendency of increase, but found to be almost independent of the separation of pairs beyond 100 kpc. The constancy of $M/L$ beyond 100 kpc may indicate that the typical halo size of spiral galaxies is less than $\sim 100$ kpc.Comment: 18 pages + 8 figures, to appear in ApJ Vol. 516 (May 10