3D-4D Interlinkage Of qqq Wave Functions Under 3D Support For Pairwise Bethe-Salpeter Kernels

Using the method of Green's functions within a Bethe-Salpeter framework characterized by a pairwise qq interaction with a Lorentz-covariant 3D support to its kernel, the 4D BS wave function for a system of 3 identical relativistic spinless quarks is reconstructed from the corresponding 3D form which satisfies a fully connected 3D BSE. This result is a 3-body generalization of a similar 2-body result found earlier under identical conditions of a 3D support to the corresponding qq-bar BS kernel under Covariant Instaneity (CIA for short). (The generalization from spinless to fermion quarks is straightforward). To set the CIA with 3D BS kernel support ansatz in the context of contemporary approaches to the qqq baryon problem, a model scalar 4D qqq BSE with pairwise contact interactions to simulate the NJL-Faddeev equations is worked out fully, and a comparison of both vertex functions shows that the CIA vertex reduces exactly to the NJL form in the limit of zero spatial range. This consistency check on the CIA vertex function is part of a fuller accounting for its mathematical structure whose physical motivation is traceable to the role of `spectroscopy' as an integral part of the dynamics.Comment: 20 pages, Latex, submitted via the account of K.-C. Yan

No Massive Black-Hole in Cygnus X-3

There has been a recent suggestion that Cyg X-3 contains a black hole (BH) of mass ~17 solar mass. This interpretation is closely linked to a previous claim that Cyg X-3 contains a Wolf-Rayet star of mass ~ 10 solar mass. The latter interpretation would imply that the X-ray source in this close binary (P = 4.8 hr) is enshrouded by a relatively cool superstrong wind > 10^{-5} solar mass/yr. It can be shown that such a wind would be completely opaque to the low energy X-rays observed from the source and hence the Wolf-Rayet hypothesis can not be a correct one. By pursuing the same argument it also follows that the compact object must be of modest mass ruling out the existence of a massive BH in Cyg X-3. Note, however, that at present we can not strictly rule out the probable existence of stellar mass BH in Cyg X-3 or any other X-ray binary which are believed to contain a neutron star as the compact object. Yet, a more probable scenario for Cyg X-3 would be one where the compact object is a canonical neutron star (NS) and the companion is an extremely low mass dwarf, ~0.001 solar mass, much like PSR 1957+20.Comment: 9 pages, Latex using aasms4.sty file, scheduled to be published in Astophys. J. on May 20, 1998 issu

Age-related reversal of postural adjustment characteristics during motor imagery

Physical and imagined movements show similar behavioral constraints and neurophysiological activation patterns. An inhibition mechanism is thought to suppress overt movement during m otor imagery, but it does not effectively suppress autonomic or postural adjustments. Inhibitory processes and postural stability both deteriorate with age. Thus, older people’s balance is potentially vulnerable to interference from postural adjustments in duced by thoughts about past or future actions. Here, young and older adults stood upright and executed or imagined manual reaching movements. Reported arm movement time (MT) of all participants increased with target distance. Older participants reported longer MT than young participants when executing arm movements, but not when imagining them. Older adults’ anteroposterior (AP) and mediolateral (ML) postural sway was higher than young adults’ at baseline, but their AP sway fell below their baseline level during manual imagery. In contrast, young adults’ AP sway increased during imagery relative to their baseline. A similar tendency to reduce sway in the ML direction was also observed in older adults during imagery in a challenging stance. These results suggest that postural response during manual motor imagery reverses direction with age. Motor imagery and action planning are ubiquitous tasks, and older people are likely to spend more time engaged in them. The shift toward restricting body sway during these tasks is akin to a postural threat response with the potential to interfere with balance during activities of daily living

Changing trends in ferro-alloy consumption in an integrated steel plant

Ferro-alloy addition for the purpose of deoxidation or alloying, is an integral part of steelmaking. The grade of alloy used is influenced by technical, economic and avail-ability considerations.In addition to ferro-alloys, requir-ements can also be met partly from plant return scrap

Extra costs of living with a disability: A review and agenda for research

BACKGROUND: There has been a growing interest in disability and poverty on the international research and policy stages. Poverty assessments for persons with disabilities may be affected by the experience of extra costs associated with a disability. OBJECTIVE: This article provides a systematized review of the global literature on the direct costs associated with living with a disability at the individual or household level. METHODS: We searched three databases for peer-reviewed journal articles that estimated extra costs associated with disability: Econlit, SocIndex and PubMed. RESULTS: We found 20 such studies conducted in 10 countries. These studies were predominantly from high-income countries. Although studies were heterogeneous (e.g., in terms of disability measures and cost methodologies), estimated costs were sizeable and some patterns were consistent across studies. Costs varied according to the severity of disability, life cycle and household composition. Highest costs were observed among persons with severe disabilities, and among persons with disabilities living alone or in small sized households. CONCLUSIONS: More quantitative evidence is needed using rigorous methods, for instance evidence based on longitudinal data and as part of policy evaluations. More internationally comparable data on disability is required for the quantitative evidence to develop, especially in low- and middle-income countries where studies are scarce. Qualitative and participatory research is also needed, especially to investigate unmet needs, and the consequences of extra costs

Inferring object properties from human interaction and transferring them to new motions

Humans regularly interact with their surrounding objects. Such interactions often result in strongly correlated motions between humans and the interacting objects. We thus ask: “Is it possible to infer object properties from skeletal motion alone, even without seeing the interacting object itself?” In this paper, we present a fine-grained action recognition method that learns to infer such latent object properties from human interaction motion alone. This inference allows us to disentangle the motion from the object property and transfer object properties to a given motion. We collected a large number of videos and 3D skeletal motions of performing actors using an inertial motion capture device. We analyzed similar actions and learned subtle differences between them to reveal latent properties of the interacting objects. In particular, we learned to identify the interacting object, by estimating its weight, or its spillability. Our results clearly demonstrate that motions and interacting objects are highly correlated and that related object latent properties can be inferred from 3D skeleton sequences alone, leading to new synthesis possibilities for motions involving human interaction

The Equilibrium Distribution of Gas Molecules Adsorbed on an Active Surface

We evaluate the exact equilibrium distribution of gas molecules adsorbed on an active surface with an infinite number of attachment sites. Our result is a Poisson distribution having mean $X = {\mu P P_s \over P_e}$, with $\mu$ the mean gas density, $P_s$ the sticking probability, $P_e$ the evaporation probability in a time interval $\tau$, and $P$ Smoluchowski's exit probability in time interval $\tau$ for the surface in question. We then solve for the case of a finite number of attachment sites using the mean field approximation, recovering in this case the Langmuir isotherm.Comment: 14 pages done in late

Off-Shell Rho-Omega Mixing Through Quark Loops With Non-Perturbative Meson Vertex And Quark Mass Functions

The momemtum dependence of the off-shell $\rho$-$\omega$ mixing amplitude is calculated through a two-quark loop diagram, using non-perturbative meson-quark vertex functions for the $\rho$ and $\omega$ mesons, as well as non-perturbative quark propagators. Both these quantities are generated self-consistently through an interlinked BSE-cum-SDE approach with a 3D support for the BSE kernel with two basic constants which are pre- checked against a wide cross section of both meson and baryon spectra within a common structural framework for their respective 3D BSE's. With this pre-calibration, the on-shell strength works out at -2.434$\delta(m_q^2)$ in units of the change in "constituent mass squared", which is consistent with the $e^+e^-$ to $\pi^+\pi^-$ data for a u-d mass difference of ~4 MeV ,while the relative off-shell strength (0.99 $\pm$ 0.01) lies midway between quark-loop and QCD-SR results. We also calculate the photon-mediated $\rho$-$\omega$ propagator whose off-shell structure has an additional pole at $q^2$=0. The implications of these results vis-a-vis related investigations are discussed.Comment: 12 Pages, latex file, NTUTH-94-0

Strong feedback and current noise in nanoelectromechanical systems

We demonstrate the feasibility of a strong feedback regime for a single-electron tunneling device weakly coupled to an underdamped single-mode oscillator. In this regime, mechanical oscillations are generated and the current is strongly modified whereas the current noise is parametrically big with respect to the Poisson value. This regime requires energy dependence of the tunnel amplitudes. For sufficiently fast tunnel rates the mechanical contribution to current noise can exceed the Poisson value even beyond the strong feedback regime.Comment: 4 pages, 3 figure