Winds and Waves (4 Min - 11 Yrs) in the Upper Middle Atmosphere (60-110 Km) at Saskatoon, Canada (52 Deg N, 107 Deg W): MF Radar (2.2 Mhz) Soundings 1973 - 1983

Examples of gravity waves (GW), tides, planetary waves (PW), and circulation effects in the upper middle atmosphere are presented. Energy densities of GW, tides, and PW are compared. Fourier and spectral analyses are applied to the data

Multiresolution analysis in statistical mechanics. I. Using wavelets to calculate thermodynamic properties

The wavelet transform, a family of orthonormal bases, is introduced as a technique for performing multiresolution analysis in statistical mechanics. The wavelet transform is a hierarchical technique designed to separate data sets into sets representing local averages and local differences. Although one-to-one transformations of data sets are possible, the advantage of the wavelet transform is as an approximation scheme for the efficient calculation of thermodynamic and ensemble properties. Even under the most drastic of approximations, the resulting errors in the values obtained for average absolute magnetization, free energy, and heat capacity are on the order of 10%, with a corresponding computational efficiency gain of two orders of magnitude for a system such as a $4\times 4$ Ising lattice. In addition, the errors in the results tend toward zero in the neighborhood of fixed points, as determined by renormalization group theory.Comment: 13 pages plus 7 figures (PNG

How many black holes fit on the head of a pin?

The Bekenstein-Hawking entropy of certain black holes can be computed microscopically in string theory by mapping the elusive problem of counting microstates of a strongly gravitating black hole to the tractable problem of counting microstates of a weakly coupled D-brane system, which has no event horizon, and indeed comfortably fits on the head of a pin. We show here that, contrary to widely held beliefs, the entropy of spherically symmetric black holes can easily be dwarfed by that of stationary multi-black-hole ``molecules'' of the same total charge and energy. Thus, the corresponding pin-sized D-brane systems do not even approximately count the microstates of a single black hole, but rather those of a zoo of entropically dominant multicentered configurations.Comment: 4 pages, fourth prize in the Gravity Research Foundation Essay competition 200

Barriers block the effect of joint attention on working memory:Perspective taking matters

Joint focus of attention between two individuals can influence the way that observers attend, encode, and value items. Using a nonpredictive gaze cuing task we previously found that working memory (WM) was better for jointly attended (validly cued) versus invalidly cued colored squares. Here we examine whether this influence of gaze on WM is driven by observers sharing the perspective of the face cue (mental state account), or simply by increased attention to the cued location (social attention account). To manipulate perspective taking, a closed barrier obstructed the cue face’s view of the memoranda, while an open barrier allowed the cue face to “see” the colors. A central cue face flanked by two identical barriers looked left or right, followed 500 ms later by colored squares for encoding which appeared equally often in the validly and invalidly cued locations. After a blank 1000 ms maintenance interval, participants stated whether a probe color was present or not in the preceding display. When the barrier was open, WM was significantly impaired for invalidly versus validly cued items. When the barrier was closed, the effect of gaze cues on WM was abolished. In contrast, further experiments showed a significant cuing effect on the speed of simple target localization and color discrimination regardless of barrier type. These findings support the mental state account of joint attention in WM, whereby the attentional focus of another alters WM via higher level engagement with the second person perspective. A goal-specific model of perspective taking is proposed

Joint attention enhances visual working memory.

Joint attention—the mutual focus of 2 individuals on an item—speeds detection and discrimination of target information. However, what happens to that information beyond the initial perceptual episode? To fully comprehend and engage with our immediate environment also requires working memory (WM), which integrates information from second to second to create a coherent and fluid picture of our world. Yet, no research exists at present that examines how joint attention directly impacts WM. To investigate this, we created a unique paradigm that combines gaze cues with a traditional visual WM task. A central, direct gaze ‘cue’ face looked left or right, followed 500 ms later by 4, 6, or 8 colored squares presented on one side of the face for encoding. Crucially, the cue face either looked at the squares (valid cue) or looked away from them (invalid cue). A no shift (direct gaze) condition served as a baseline. After a blank 1,000 ms maintenance interval, participants stated whether a single test square color was present or not in the preceding display. WM accuracy was significantly greater for colors encoded in the valid versus invalid and direct conditions. Further experiments showed that an arrow cue and a low-level motion cue—both shown to reliably orient attention—did not reliably modulate WM, indicating that social cues are more powerful. This study provides the first direct evidence that sharing the focus of another individual establishes a point of reference from which information is advantageously encoded into WM

Determination of the Δ(1232)\Delta(1232) axial and pseudoscalar form factors from lattice QCD

We present a lattice QCD calculation of the $\Delta(1232)$ matrix elements of the axial-vector and pseudoscalar currents. The decomposition of these matrix elements into the appropriate Lorentz invariant form factors is carried out and the techniques to calculate the form factors are developed and tested using quenched configurations. Results are obtained for 2+1 domain wall fermions and within a hybrid scheme with domain wall valence and staggered sea quarks. Two Goldberger-Treiman type relations connecting the axial to the pseudoscalar effective couplings are derived. These and further relations based on the pion-pole dominance hypothesis are examined using the lattice QCD results, finding support for their validity. Utilizing lattice QCD results on the axial charges of the nucleon and the $\Delta$, as well as the nucleon-to-$\Delta$ transition coupling constant, we perform a combined chiral fit to all three quantities and study their pion mass dependence as the chiral limit is approached

Quantum Mutual Information Capacity for High Dimensional Entangled States

High dimensional Hilbert spaces used for quantum communication channels offer the possibility of large data transmission capabilities. We propose a method of characterizing the channel capacity of an entangled photonic state in high dimensional position and momentum bases. We use this method to measure the channel capacity of a parametric downconversion state, achieving a channel capacity over 7 bits/photon in either the position or momentum basis, by measuring in up to 576 dimensions per detector. The channel violated an entropic separability bound, suggesting the performance cannot be replicated classically.Comment: 5 pages, 2 figure

An instrument to measure the charge, and energy spectrum (20-1000 GeV/a) of the cosmic ray species oxygen to iron

BUGS-4 (Bristol University Gas Scintillator-4) made its maiden engineering flight from Fort Summer (NM) on the 29th of September 1993. The instrument was consumed by fire after striking a power line during landing following 24 hours at float. The analysis of the telemetered data from this sophisticated instrument is a demanding task. Early analysis was compromised by electronic artifacts. Unravelling these problems has been difficult and time consuming, especially as the flight hardware was burned beyond salvage, but is is an essential preliminary to analysis. During this report period we have concentrated on a small sub-set of data (the first 30,000 events; 90 minutes at float), and developed software algorithms to correct systematic errors. Using these corrected events we have begun to develop the analysis algorithms. Although the analysis is preliminary, and restricted to the first 30,000 events, the results are encouraging, and suggest the design concepts are well matched to this application. Further work will refine the analysis, and allow quantitative evaluation of the concepts employed in BUGS-4 for applicability to future instruments. We believe this work will justify fabrication of a new instrument employing techniques deployed on BUGS-4

On the Nature of the Strong Emission-Line Galaxies in Cluster Cl 0024+1654: Are Some the Progenitors of Low Mass Spheroidals?

We present new size, line ratio, and velocity width measurements for six strong emission-line galaxies in the galaxy cluster, Cl 0024+1654, at redshift z~0.4. The velocity widths from Keck spectra are all narrow (30<sigma<120 km/s), with three profiles showing double peaks. Four galaxies have low masses (M<10^{10} Mo). Whereas three galaxies were previously reported to be possible AGNs, none exhibit AGN-like emission line ratios or velocity widths. Two or three appear as very blue spirals with the remainder more akin to luminous H-II galaxies undergoing a strong burst of star formation. We propose that after the burst subsides, these galaxies will transform into quiescent dwarfs, and are thus progenitors of some cluster spheroidals (We adopt the nomenclature suggested by Kormendy & Bender (1994), i.e., low-density, dwarf ellipsoidal galaxies like NGC 205 are called `spheroidals' instead of `dwarf ellipticals') seen today.Comment: 14 pages + 2 figures + 1 table, LaTeX, Acc. for publ. in ApJL also available at http://www.ucolick.org/~deep/papers/papers.htm