"Low-state" Black Hole Accretion in Nearby Galaxies

I summarize the main observational properties of low-luminosity AGNs in nearby galaxies to argue that they are the high-mass analogs of black hole X-ray binaries in the "low/hard" state. The principal characteristics of low-state AGNs can be accommodated with a scenario in which the central engine is comprised of three components: an optically thick, geometrically accretion disk with a truncated inner radius, a radiatively inefficient flow, and a compact jet.Comment: 8 pages. To appear in From X-ray Binaries to Quasars: Black Hole Accretion on All Mass Scales, ed. T. J. Maccarone, R. P. Fender, and L. C. Ho (Dordrecht: Kluwer

Comparing seated pressures in daily wheelchair and sports equipment and investigating the skin protective effects of padded shorts.

Background: Adaptive sports are promoted for individuals with spinal cord injury to increase overall health and prevent cardiovascular and metabolic diseases, but the potential risk of pressure ulcer development with adaptive equipment (AE) is a concern. Current research has found seated pressures in AE that exceed clinically accepted values but no studies have measured pressure with a padded short to assess for its potential pressure reducing effects. Objective: Our study sought to evaluate average and peak seating pressure in both static and dynamic sport-specific positions, with and without the presence of three types of over-the-counter padded bicycle shorts, in multiple types of adaptive equipment (AE): Hand cycle, quad rugby, basketball, and mountain hand cycle. Methods: Part One. Pre/Post test design with subjects as their own control. Eight adults with SCI (C5-T6) were pressure mapped under static and dynamic conditions in their daily use wheelchair (WC) and AE. Three conditions were mapped: Daily WC, AE without bicycle shorts, and AE with shorts. AE included: Hand-cycle, quad rugby, basketball, and mountain hand-cycle. Part Two. Static pressure readings in a hand-cycle were taken on 16 able-bodied subjects with and without an impact short and a full-coverage padded short. Part three. Single subject with T5 SCI was pressure mapped in static and dynamic conditions with and without the full-coverage padded short in a basketball chair and mountain hand-cycle. Average pressure (AP) and peak pressure (PP) recordings were taken for 60 seconds (400 frames) using the TekScan Pressure Mapping System. For static recordings the participants were instructed to sit still, while for dynamic recordings participants simulated sport or activity specific movements. Results: Part 1. Significant differences were found between the daily chair and AE for both AP and PP in the static condition (p \u3c 0.05), as well as AP in the dynamic condition (p Part 2. The impact short significantly increased static PP and AP (p0.05). Part 3. The full-coverage padded short increased AP and PP in the basketball chair, decreased AP in the mountain hand cycle and increased PP in the mountain hand cycle. Discussion: Pressure differences between daily WC and AE in static conditions suggests that athletes who are not moving or sitting on the sidelines in their AE may be at greater risk of tissue breakdown than athletes who are playing and experiencing pressure-relieving positions during movement. Padded shorts as a method to reduce PP and AP yielded variable results which may have been influenced by type of AE and posture in the AE. Thus seated posture may influence the pressure relieving capabilities of a padded short. Conclusion: Donning a padded short as a method of skin protection yields highly variable changes in PP and AP and pressure mapping should be performed prior to use in AE by the SCI population. Works Cited: Berthold, J., Dicianno, B.E. & Cooper, R.A. (2013). Pressure mapping to assess seated pressure distributions and the potential risk for skin ulceration in a population of sledge hockey players and control subjects. Disability and Rehabilitation. Assistive Technology, 8(5), 387-39http://doi.org/10.3109/17483107.2013.769123 Darrah, S.D., Dcianno, B.E., Berthold, J., McCoy, A., Haas, M., & Cooper, R.A. (2016). Measuring static seated pressure distributions and risk for skin pressure ulceration in ice sledge hockey players. Disability and Rehabilitation. Assistive Technology, 11(3), 241-246. http://doi.org/10.3109/17483107.2014.92193

A Paraconsistent Higher Order Logic

Classical logic predicts that everything (thus nothing useful at all) follows from inconsistency. A paraconsistent logic is a logic where an inconsistency does not lead to such an explosion, and since in practice consistency is difficult to achieve there are many potential applications of paraconsistent logics in knowledge-based systems, logical semantics of natural language, etc. Higher order logics have the advantages of being expressive and with several automated theorem provers available. Also the type system can be helpful. We present a concise description of a paraconsistent higher order logic with countable infinite indeterminacy, where each basic formula can get its own indeterminate truth value (or as we prefer: truth code). The meaning of the logical operators is new and rather different from traditional many-valued logics as well as from logics based on bilattices. The adequacy of the logic is examined by a case study in the domain of medicine. Thus we try to build a bridge between the HOL and MVL communities. A sequent calculus is proposed based on recent work by Muskens.Comment: Originally in the proceedings of PCL 2002, editors Hendrik Decker, Joergen Villadsen, Toshiharu Waragai (http://floc02.diku.dk/PCL/). Correcte

Symmetric angular momentum coupling, the quantum volume operator and the 7-spin network: a computational perspective

A unified vision of the symmetric coupling of angular momenta and of the quantum mechanical volume operator is illustrated. The focus is on the quantum mechanical angular momentum theory of Wigner's 6j symbols and on the volume operator of the symmetric coupling in spin network approaches: here, crucial to our presentation are an appreciation of the role of the Racah sum rule and the simplification arising from the use of Regge symmetry. The projective geometry approach permits the introduction of a symmetric representation of a network of seven spins or angular momenta. Results of extensive computational investigations are summarized, presented and briefly discussed.Comment: 15 pages, 10 figures, presented at ICCSA 2014, 14th International Conference on Computational Science and Application

Study of Dipole Resonance Strength in 12-C via the Reactions 12-C(pol.p,p'c)

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Perturbative QCD and factorization of coherent pion photoproduction on the deuteron

We analyze the predictions of perturbative QCD for pion photoproduction on the deuteron, gamma D -> pi^0 D, at large momentum transfer using the reduced amplitude formalism. The cluster decomposition of the deuteron wave function at small binding only allows the nuclear coherent process to proceed if each nucleon absorbs an equal fraction of the overall momentum transfer. Furthermore, each nucleon must scatter while remaining close to its mass shell. Thus the nuclear photoproduction amplitude, M_{gamma D -> pi^0 D}(u,t), factorizes as a product of three factors: (1) the nucleon photoproduction amplitude, M_{gamma N_1 -> pi^0 N_1}(u/4,t/4), at half of the overall momentum transfer, (2) a nucleon form factor, F_{N_2}(t/4), at half the overall momentum transfer, and (3) the reduced deuteron form factor, f_d(t), which according to perturbative QCD, has the same monopole falloff as a meson form factor. A comparison with the recent JLAB data for gamma D -> pi^0 D of Meekins et al. [Phys. Rev. C 60, 052201 (1999)] and the available gamma p -> pi^0 p data shows good agreement between the perturbative QCD prediction and experiment over a large range of momentum transfers and center of mass angles. The reduced amplitude prediction is consistent with the constituent counting rule, p^11_T M_{gamma D -> pi^0 D} -> F(theta_cm), at large momentum transfer. This is found to be consistent with measurements for photon lab energies E_gamma > 3 GeV at theta_cm=90 degrees and \elab > 10 GeV at 136 degrees.Comment: RevTeX 3.1, 17 pages, 6 figures; v2: incorporates minor changes as version accepted by Phys Rev

Level Sets of the Takagi Function: Local Level Sets

The Takagi function \tau : [0, 1] \to [0, 1] is a continuous non-differentiable function constructed by Takagi in 1903. The level sets L(y) = {x : \tau(x) = y} of the Takagi function \tau(x) are studied by introducing a notion of local level set into which level sets are partitioned. Local level sets are simple to analyze, reducing questions to understanding the relation of level sets to local level sets, which is more complicated. It is known that for a "generic" full Lebesgue measure set of ordinates y, the level sets are finite sets. Here it is shown for a "generic" full Lebesgue measure set of abscissas x, the level set L(\tau(x)) is uncountable. An interesting singular monotone function is constructed, associated to local level sets, and is used to show the expected number of local level sets at a random level y is exactly 3/2.Comment: 32 pages, 2 figures, 1 table. Latest version has updated equation numbering. The final publication will soon be available at springerlink.co