20,403 research outputs found
Voyager 1 imaging and IRIS observations of Jovian methane absorption and thermal emission: Implications for cloud structure
Images from three filters of the Voyager 1 wide angle camera are used to measure the continuum reflectivity and spectral gradient near 6000 A and the 6190 A band methane/continuum ratio for a variety of cloud features in Jupiter's atmosphere. The dark barge features in the North Equatorial Belt have anomalously strong positive continuum spectral gradients suggesting unique composition. Methane absorption is shown at unprecedented spatial scales for the Great Red Spot and its immediate environment, for a dark barge feature in the North Equatorial Belt, and for two hot spot and plume regions in the North Equatorial Belt. Methane absorption and five micrometer emission are correlated in the vicinity of the Great Red Spot but are anticorrelated in one of the plume hot spot regions. Methane absorption and simultaneous maps of five micrometer brightness temperature is quantitatively compared to realistic cloud structure models which include multiple scattering at five micrometer as well as in the visible. Variability in H2 quadrupole lines are also investigated
A microcontroller system for investigating the catch effect: Functional electrical stimulation of the common peroneal nerve
Correction of drop foot in hemiplegic gait is achieved by electrical stimulation of the common peroneal nerve with a series of pulses at a fixed frequency. However, during normal gait, the electromyographic signals from the tibialis anterior muscle indicate that muscle force is not constant but varies during the swing phase. The application of double pulses for the correction of drop foot may enhance the gait by generating greater torque at the ankle and thereby increase the efficiency of the stimulation with reduced fatigue. A flexible controller has been designed around the Odstock Drop Foot Stimulator to deliver different profiles of pulses implementing doublets and optimum series. A peripheral interface controller (PIC) microcontroller with some external circuits has been designed and tested to accommodate six profiles. Preliminary results of the measurements from a normal subject seated in a multi-moment chair (an isometric torque measurement device) indicate that profiles containing doublets and optimum spaced pulses look favourable for clinical use
Renormalization of heavy-light currents in moving NRQCD
Heavy-light decays such as , and can be used to constrain the parameters of the Standard
Model and in indirect searches for new physics. While the precision of
experimental results has improved over the last years this has still to be
matched by equally precise theoretical predictions. The calculation of
heavy-light form factors is currently carried out in lattice QCD. Due to its
small Compton wavelength we discretize the heavy quark in an effective
non-relativistic theory. By formulating the theory in a moving frame of
reference discretization errors in the final state are reduced at large recoil.
Over the last years the formalism has been improved and tested extensively.
Systematic uncertainties are reduced by renormalizing the m(oving)NRQCD action
and heavy-light decay operators. The theory differs from QCD only for large
loop momenta at the order of the lattice cutoff and the calculation can be
carried out in perturbation theory as an expansion in the strong coupling
constant. In this paper we calculate the one loop corrections to the
heavy-light vector and tensor operator. Due to the complexity of the action the
generation of lattice Feynman rules is automated and loop integrals are solved
by the adaptive Monte Carlo integrator VEGAS. We discuss the infrared and
ultraviolet divergences in the loop integrals both in the continuum and on the
lattice. The light quarks are discretized in the ASQTad and highly improved
staggered quark (HISQ) action; the formalism is easily extended to other quark
actions.Comment: 24 pages, 11 figures. Published in Phys. Rev. D. Corrected a typo in
eqn. (51
Enhanced winnings in a mixed-ability population playing a minority game
We study a mixed population of adaptive agents with small and large memories,
competing in a minority game. If the agents are sufficiently adaptive, we find
that the average winnings per agent can exceed that obtainable in the
corresponding pure populations. In contrast to the pure population, the average
success rate of the large-memory agents can be greater than 50 percent. The
present results are not reproduced if the agents are fed a random history,
thereby demonstrating the importance of memory in this system.Comment: 9 pages Latex + 2 figure
Farm and Forest Fair Educates Fifth Graders about Natural Resource Issues
The Farm and Forest Fair educational program was developed to provide an objective view of the importance and impact of natural resource industries and promote an understanding of the issues regarding natural resource use. The targeted audience is fifth grade youth, teachers, and parents. Participants rotate through 10 stations in 9-minute intervals. Stations are staffed by agriculture- or forest-based industry personnel who demonstrate their area of natural resource involvement utilizing visual aids and hands-on learning techniques. Teachers, presenters, and youth are evaluated each year. Student pre- and post-test results indicate knowledge level increases of 21%
Analysis of Probabilistic Basic Parallel Processes
Basic Parallel Processes (BPPs) are a well-known subclass of Petri Nets. They
are the simplest common model of concurrent programs that allows unbounded
spawning of processes. In the probabilistic version of BPPs, every process
generates other processes according to a probability distribution. We study the
decidability and complexity of fundamental qualitative problems over
probabilistic BPPs -- in particular reachability with probability 1 of
different classes of target sets (e.g. upward-closed sets). Our results concern
both the Markov-chain model, where processes are scheduled randomly, and the
MDP model, where processes are picked by a scheduler.Comment: This is the technical report for a FoSSaCS'14 pape
Recommended from our members
Evolution of the eyes of vipers with and without infrared-sensing pit organs
We examined lens and brille transmittance, photoreceptors, visual pigments, and visual opsin gene sequences of viperid snakes with and without infrared-sensing pit organs. Ocular media transmittance is high in both groups. Contrary to previous reports, small as well as large single cones occur in pit vipers. Non-pit vipers differ from pit vipers in having a twotiered retina, but few taxa have been examined for this poorly understood feature. All vipers sampled express rh1, sws1 and lws visual opsin genes. Opsin spectral tuning varies but not in accordance with the presence/absence of pit organs, and not always as predicted from gene sequences. The visual opsin genes were generally under purifying selection, with positive selection at spectral tuning amino acids in RH1 and SWS1 opsins, and at retinal pocket stabilization sites in RH1 or LWS (and without substantial differences between pit and nonpit vipers). Lack of evidence for sensory trade-off between viperid eyes (in the aspects examined) and pit organs might be explained by the high degree of neural integration of vision and infrared detection; the latter representing an elaboration of an existing sense with addition of a novel sense organ, rather than involving the evolution of a wholly novel sensory system
Power Dependent Resonant Frequency of a Microwave Cavity due to Magnetic Levitation
Levitation of a magnet by superconductor has been an active area of research
to explore the quantum mechanical phenomenon. One of the techniques used is to
measure the levitation of a magnet placed inside the superconducting microwave
cavity. The levitation height can be probed by measuring the change in
microwave frequency. Here, we report measurements of the change in resonance
frequency of the microwave cavity with the Meissner-levitated permanent magnet.
The change in resonant frequency and quality factor was measured as a function
of input power and temperature. The change in resonate frequency is likely due
to the interaction of the magnet with the radio-frequency field inside the
microwave cavity
Space construction system analysis. Part 2: Platform definition
The top level system requirements are summarized and the accompanying conceptual design for an engineering and technology verification platform (ETVP) system is presented. An encompassing statement of the system objectives which drive the system requirements is presented and the major mission and subsystem requirements are described with emphasis on the advanced communications technology mission payload. The platform design is defined and used as a reference configuration for an end to space construction analyses. The preferred construction methods and processes, the important interactions between the platform design and the construction system design and operation, and the technology development efforts required to support the design and space construction of the ETVP are outlined
Abelian Monopoles in SU(2) Lattice Gauge Theory as Physical Objects
By numerical calculations we show that the abelian monopole currents are
locally correlated with the density of SU(2) lattice action. The correlations
are larger by the order of magnitude in the maximal abelian projection than in
the projections which correspond to the diagonalization of Polyakov line and to
the diagonalization of the plaquette. These facts show that (at least) in the
maximal abelian projection the monopoles are the physical objects, they carry
the SU(2) action. The larger value of \beta, the larger the relative action
carried by monopole. Calculations on the asymmetric lattice show that this
correlation exists also in the deconfinement phase of gluodynamics.Comment: 6 pages, RevTeX, 3 figures, uses epsf.sty; to be published in
Phys.Rev.Lett., replaced to match version accepted for publicatio
- …