717 research outputs found

    Global digital data sets of soil type, soil texture, surface slope and other properties: Documentation of archived data tape

    Get PDF
    The file structure and coding of four soils data sets derived from the Zobler (1986) world soil file is described. The data were digitized on a one-degree square grid. They are suitable for large-area studies such as climate research with general circulation models, as well as in forestry, agriculture, soils, and hydrology. The first file is a data set of codes for soil unit, land-ice, or water, for all the one-degree square cells on Earth. The second file is a data set of codes for texture, land-ice, or water, for the same soil units. The third file is a data set of codes for slope, land-ice, or water for the same units. The fourth file is the SOILWRLD data set, containing information on soil properties of land cells of both Matthews' and Food and Agriculture Organization (FAO) sources. The fourth file reconciles land-classification differences between the two and has missing data filled in

    Reactive direction control for a mobile robot: A locust-like control of escape direction emerges when a bilateral pair of model locust visual neurons are integrated

    Get PDF
    Locusts possess a bilateral pair of uniquely identifiable visual neurons that respond vigorously to the image of an approaching object. These neurons are called the lobula giant movement detectors (LGMDs). The locust LGMDs have been extensively studied and this has lead to the development of an LGMD model for use as an artificial collision detector in robotic applications. To date, robots have been equipped with only a single, central artificial LGMD sensor, and this triggers a non-directional stop or rotation when a potentially colliding object is detected. Clearly, for a robot to behave autonomously, it must react differently to stimuli approaching from different directions. In this study, we implement a bilateral pair of LGMD models in Khepera robots equipped with normal and panoramic cameras. We integrate the responses of these LGMD models using methodologies inspired by research on escape direction control in cockroaches. Using ‘randomised winner-take-all’ or ‘steering wheel’ algorithms for LGMD model integration, the khepera robots could escape an approaching threat in real time and with a similar distribution of escape directions as real locusts. We also found that by optimising these algorithms, we could use them to integrate the left and right DCMD responses of real jumping locusts offline and reproduce the actual escape directions that the locusts took in a particular trial. Our results significantly advance the development of an artificial collision detection and evasion system based on the locust LGMD by allowing it reactive control over robot behaviour. The success of this approach may also indicate some important areas to be pursued in future biological research

    Sweetening the Till: The Use of Candy to Increase Restaurant Tipping

    Get PDF
    A common practice among servers in restaurants is to give their dining parties an unexpected gift in the form of candy when delivering the check. Two studies were conducted to evaluate the impact of this gesture on the tip percentages received by servers. Study 1 found that customers who received a small piece of chocolate along with the check tipped more than did customers who received no candy. Study 2 found that tips varied with the amount of the candy given to the customers as well as with the manner in which it was offered. It is argued that reciprocity is a stronger explanation for these findings than either impression management or the good mood effect

    Sensitive Search for a Permanent Muon Electric Dipole Moment

    Get PDF
    We are proposing a new method to carry out a dedicated search for a permanent electric dipole moment (EDM) of the muon with a sensitivity at a level of 10^{-24} e cm. The experimental design exploits the strong motional electric field sensed by relativistic particles in a magnetic storage ring. As a key feature, a novel technique has been invented in which the g-2 precession is compensated with radial electric field. This technique will benefit greatly when the intense muon sources advocated by the developers of the muon storage rings and the muon colliders become available.Comment: 16 pages, 3 figures. Submitted for publication in Proceedings of the International Workshop on High Intensity Muon Sources (HIMUS99), KEK, Japan, December 1-4 199

    Snowmass 2021 Computational Frontier CompF4 Topical Group Report Storage and Processing Resource Access

    Get PDF
    The Snowmass 2021 CompF4 topical group’s scope is facilities R&D, where we consider “facilities” as the hardware and software infrastructure inside the data centers plus the networking between data centers, irrespective of who owns them, and what policies are applied for using them. In other words, it includes commercial clouds, federally funded High Performance Computing (HPC) systems for all of science, and systems funded explicitly for a given experimental or theoretical program. However, we explicitly consider any data centers that are integrated into data acquisition systems or trigger of the experiments out of scope here. Those systems tend to have requirements that are quite distinct from the data center functionality required for “offline” processing and storage

    The importance of sea ice area biases in 21st century multimodel projections of Antarctic temperature and precipitation

    Get PDF
    Climate models exhibit large biases in sea ice area (SIA) in their historical simulations. This study explores the impacts of these biases on multimodel uncertainty in Coupled Model Intercomparison Project phase 5 (CMIP5) ensemble projections of 21st century change in Antarctic surface temperature, net precipitation, and SIA. The analysis is based on time slice climatologies in the Representative Concentration Pathway 8.5 future scenario (2070–2099) and historical (1970–1999) simulations across 37 different CMIP5 models. Projected changes in net precipitation, temperature, and SIA are found to be strongly associated with simulated historical mean SIA (e.g., cross-model correlations of r = 0.77, 0.71, and −0.85, respectively). Furthermore, historical SIA bias is found to have a large impact on the simulated ratio between net precipitation response and temperature response. This ratio is smaller in models with smaller-than-observed SIA. These strong emergent relationships on SIA bias could, if found to be physically robust, be exploited to give more precise climate projections for Antarctica

    The Muon Anomalous Magnetic Moment and the Standard Model

    Full text link
    The muon anomalous magnetic moment measurement, when compared with theory, can be used to test many extensions to the standard model. The most recent measurement made by the Brookhaven E821 Collaboration reduces the uncertainty on the world average of a_mu to 0.7 ppm, comparable in precision to theory. This paper describes the experiment and the current theoretical efforts to establish a correct standard model reference value for the muon anomaly.Comment: Plenary Talk; PANIC'02 XVI Particles and Nuclear International Conference, Osaka, Japan; Sept. 30 - Oct. 4, 2002; Report describes the published 0.7 ppm result and updates the theory statu

    Search for Lorentz and CPT Violation Effects in Muon Spin Precession

    Full text link
    The spin precession frequency of muons stored in the (g−2)(g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero Δωa\Delta\omega_{a} (=ωaÎŒ+−ωaΌ−\omega_{a}^{\mu^{+}}-\omega_{a}^{\mu^{-}}); and a sidereal variation of ωaΌ±\omega_{a}^{\mu^{\pm}}. No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ=−(1.0±1.1)×10−23b_{Z} =-(1.0 \pm 1.1)\times 10^{-23} GeV; (mÎŒdZ0+HXY)=(1.8±6.0×10−23)(m_{\mu}d_{Z0}+H_{XY}) = (1.8 \pm 6.0 \times 10^{-23}) GeV; and the 95% confidence level limits bˇ⊄Ό+<1.4×10−24\check{b}_{\perp}^{\mu^{+}}< 1.4 \times 10^{-24} GeV and bˇ⊄Ό−<2.6×10−24\check{b}_{\perp}^{\mu^{-}} < 2.6 \times 10^{-24} GeV.Comment: 5 pages, 3 figures, submitted to Physical Review Letters, Modified to answer the referees suggestion

    An Improved Limit on the Muon Electric Dipole Moment

    Get PDF
    Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from the muon g-2 storage ring at Brookhaven National Laboratory. Details on the experimental apparatus and the three analyses are presented. Since the individual results on the positive and negative muon, as well as the combined result, d=-0.1(0.9)E-19 e-cm, are all consistent with zero, we set a new muon EDM limit, |d| < 1.9E-19 e-cm (95% C.L.). This represents a factor of 5 improvement over the previous best limit on the muon EDM.Comment: 19 pages, 15 figures, 7 table

    Search for Lorentz and CPT Violation Effects in Muon Spin Precession

    Full text link
    The spin precession frequency of muons stored in the (g−2)(g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero Δωa\Delta\omega_{a} (=ωaÎŒ+−ωaΌ−\omega_{a}^{\mu^{+}}-\omega_{a}^{\mu^{-}}); and a sidereal variation of ωaΌ±\omega_{a}^{\mu^{\pm}}. No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ=−(1.0±1.1)×10−23b_{Z} =-(1.0 \pm 1.1)\times 10^{-23} GeV; (mÎŒdZ0+HXY)=(1.8±6.0×10−23)(m_{\mu}d_{Z0}+H_{XY}) = (1.8 \pm 6.0 \times 10^{-23}) GeV; and the 95% confidence level limits bˇ⊄Ό+<1.4×10−24\check{b}_{\perp}^{\mu^{+}}< 1.4 \times 10^{-24} GeV and bˇ⊄Ό−<2.6×10−24\check{b}_{\perp}^{\mu^{-}} < 2.6 \times 10^{-24} GeV.Comment: 5 pages, 3 figures, submitted to Physical Review Letters, Modified to answer the referees suggestion
    • 

    corecore