Cantor type functions in non-integer bases

Cantor's ternary function is generalized to arbitrary base-change functions in non-integer bases. Some of them share the curious properties of Cantor's function, while others behave quite differently

Extinction Curves, Distances, and Clumpiness of Diffuse Interstellar Dust Clouds

We present CCD photometry in UBVRI of several thousand Galactic field stars in four large (>1 degree^2) regions centered on diffuse interstellar dust clouds, commonly referred to as ``cirrus'' clouds (with optical depth A_V less than unity). Our goal in studying these stars is to investigate the properties of the cirrus clouds. A comparison of the observed stellar surface density between on-cloud and off-cloud regions as a function of apparent magnitude in each of the five bands effectively yields a measure of the extinction through each cloud. For two of the cirrus clouds, this method is used to derive UBVRI star counts-based extinction curves, and U-band counts are used to place constraints on the cloud distance. The color distribution of stars and their location in (U-B, B-V) and (B-V, V-I) color-color space are analyzed in order to determine the amount of selective extinction (reddening) caused by the cirrus. The color excesses, A_lambda-A_V, derived from stellar color histogram offsets for the four clouds, are better fit by a reddening law that rises steeply towards short wavelengths [R_V==A_V/E(B-V)<=2] than by the standard law (R_V=3.1). This may be indicative of a higher-than-average abundance of small dust grains relative to larger grains in diffuse cirrus clouds. The shape of the counts-based effective extinction curve and a comparison of different estimates of the dust optical depth (extinction optical depth derived from background star counts/colors; emission optical depth derived from far infrared measurements), are used to measure the degree of clumpiness in clouds. The set of techniques explored in this paper can be readily adapted to the Sloan Digital Sky Survey data set in order to carry out a systematic, large-scale study of cirrus clouds.Comment: 22 pages, 13 figures (postscript, gif, jpg). Accepted for publication in the Astronomical Journal, scheduled for the May 1999 issue. Full resolution postscript versions of all figures are available at http://www.ucolick.org/~arpad

Search for electric dipole moments at storage rings

Permanent electric dipole moments (EDMs) violate parity and time reversal symmetry. Within the Standard Model (SM) they are many orders of magnitude below present experimental sensitivity. Many extensions of the SM predict much larger EDMs, which are therefore an excellent probe for the existence of "new physics". Until recently it was believed that only electrically neutral systems could be used for sensitive searches of EDMs. With the introduction of a novel experimental method, high precision for charged systems will be within reach as well. The features of this method and its possibilities are discussed.Comment: Proc. EXA2011, 6 pages; http://www.springerlink.com/content/45l35376832vhrg0

Implicit relevance feedback from a multi-step search process: a use of query-logs

We evaluate the use of clickthrough information as implicit relevance feedback in sessions. We employ records of user interactions with a search system for pictures retrieval: issued queries, clicked images, and purchased content; we investigate whether and how much of the past search history should be used in a feedback loop. We also assess the benefit of using clicked data as positive tokens of relevance to the task of estimating the probability of an image to be purchased

Inclusion of non-spherical components of the Pauli blocking operator in (p,p') reactions

We present the first calculations of proton elastic and inelastic scattering in which the Pauli blocking operator contains the leading non-spherical components as well as the usual spherical (angle-averaged) part. We develop a formalism for including the contributions to the effective nucleon-nucleon interaction from the resulting new G-matrix elements that extend the usual two-nucleon spin structure and may not conserve angular momentum. We explore the consequences of parity conservation, time reversal invariance, and nucleon-nucleon antisymmetrization for the new effective interaction. Changes to the calculated cross section and spin observables are small in the energy range from 100 to 200 MeV.Comment: 24 pages, 4 figures, to be published in Physical Review

Effect of toroidal field ripple on plasma rotation in JET

Dedicated experiments on TF ripple effects on the performance of tokamak plasmas have been carried out at JET. The TF ripple was found to have a profound effect on the plasma rotation. The central Mach number, M, defined as the ratio of the rotation velocity and the thermal velocity, was found to drop as a function of TF ripple amplitude (3) from an average value of M = 0.40-0.55 for operations at the standard JET ripple of 6 = 0.08% to M = 0.25-0.40 for 6 = 0.5% and M = 0.1-0.3 for delta = 1%. TF ripple effects should be considered when estimating the plasma rotation in ITER. With standard co-current injection of neutral beam injection (NBI), plasmas were found to rotate in the co-current direction. However, for higher TF ripple amplitudes (delta similar to 1%) an area of counter rotation developed at the edge of the plasma, while the core kept its co-rotation. The edge counter rotation was found to depend, besides on the TF ripple amplitude, on the edge temperature. The observed reduction of toroidal plasma rotation with increasing TF ripple could partly be explained by TF ripple induced losses of energetic ions, injected by NBI. However, the calculated torque due to these losses was insufficient to explain the observed counter rotation and its scaling with edge parameters. It is suggested that additional TF ripple induced losses of thermal ions contribute to this effect

Microscopic Calculation of Total Ordinary Muon Capture Rates for Medium - Weight and Heavy Nuclei

Total Ordinary Muon Capture (OMC) rates are calculated on the basis of the Quasiparticle Random Phase Approximation for several spherical nuclei from 90^Zr to 208^Pb. It is shown that total OMC rates calculated with the free value of the axial-vector coupling constant g_A agree well with the experimental data for medium-size nuclei and exceed considerably the experimental rates for heavy nuclei. The sensitivity of theoretical OMC rates to the nuclear residual interactions is discussed.Comment: 27 pages and 3 figure

Search for gamma‐ray emission from AGN with COMPTEL

The COMPTEL data (∼0.7–30 MeV) were searched for emission from AGN. Four sources have been detected so far: the quasars 3C 273, 3C 279, PKS 0528+134, and the radio galaxy Centaurus A. 3C 273 and 3C 279 were detected in CGRO observation period 3 with quite different spectral shapes. There is also evidence for 3C 273 at a weak flux level in observation period 11. The quasar PKS 0528+134 was detected above 3 MeV as part of a search for AGN already observed by EGRET. Cen A was seen up to 3 MeV by combining data from different observation periods