Simulating Ability: Representing Skills in Games

Throughout the history of games, representing the abilities of the various agents acting on behalf of the players has been a central concern. With increasingly sophisticated games emerging, these simulations have become more realistic, but the underlying mechanisms are still, to a large extent, of an ad hoc nature. This paper proposes using a logistic model from psychometrics as a unified mechanism for task resolution in simulation-oriented games

Nitrate leaching under furrow irrigation as affected by crop sequence and tillage

The potential for NO3-N leaching after alfalfa (Medicago saliva L.) in irrigated crop production depends on cropping sequence and tillage practices. A 2-yr field experiment in south-central Idaho compared the NO3-N leached following alfalfa of a conventional tillage bean-bean (Phaseolus vulgaris L.) rotation with a silage corn (Zea mays L.)-winter wheat (Triticum aestivum L.) rotation in a conventional tillage or no-till system. Nitrate leaching was determined by: (i) sampling the soil solution below the root zone (1.2 and 1.5 m) using ceramic-tipped samplers and calculating the N movement from the water balance, and (ii) measuring the change in soil NO3-N at 1.35 to 4.5 m from soil samples taken in the fall and spring to 4.5 m. During the second growing season, average soil solution NO3-N concentrations (below the root zone) were 28, 4, and 10 mg L-1 for the bean-bean, corn-wheat no-till, and corn-wheat tilled treatments, respectively. The soil NO3-N in 1.35 to 3.3 m at the end of the study was 80 kg N ha-1 higher for the bean-bean treatment than for the corn-wheat treatments. The NO3-N that moved below 1.35 m during the 2 yr was 53 kg ha-1 higher for the bean-bean than for the corn-wheat treatments. The soil NO3-N in the 1.35 to 3.3 m depth after 2 yr was 21 kg ha-1 higher for the corn-wheat under conventional tillage than under the no-till system

Controlling nitrate leaching and erosion on irrigated land

New integrated agronomic cropping systems that nearly eliminate irrigation-induced erosion, significantly reduce nitrate leaching potential, increase crop utilization of nitrogen from legume sources and fertilizer, improve irrigation uniformity, decrease production costs, and increase net profits have resulted from several years of research at Kimberly, Idaho. These systems include growing corn or cereal without tillage following alfalfa to efficiently utilize nitrogen from the legume and reduce irrigation-induced erosion. Where no corn was grown following alfalfa, nitrate-N accumulated up to 550 lbs/ac in the upper 5 feet of soil compared to only 50 lbs/ac where corn was grown. Where beans were grown for two seasons following alfalfa, nitrate-N leaching was 50 lbs/ac more than where corn and then winter wheat were grown. Banding nitrogen fertilizer on the opposite side of the corn row from the irrigation furrow used all season reduced nitrate leaching as compared to where a furrow was irrigated on the same side of the row as the fertilizer band. Nitrate moves below the root zone during wet winters by deep drainage and pass through flow. Polyacrylamide (PAM) concentrations of 10 ppm or less applied into the irrigation water can almost eliminate furrow erosion, and it increases infiltration. Applying cheese whey alone and in combination with straw at whey rates of 12 gallons and straw rates of 4 lbs/100 ft of row before beginning irrigations reduced sediment loss by more than 95%

Experiences and Outcomes of Preschool Physical Education: an analysis of developmental discourses in Scottish curricular documentation

This article provides an analysis of developmental discourses underpinning preschool physical education in Scotland's Curriculum for Excellence. Implementing a post-structural perspective, the article examines the preschool experiences and outcomes related to physical education as presented in the Curriculum for Excellence ‘health and wellbeing’ documentation. The article interrogates the ways in which developmental discourses are evident throughout this and related documentation and how these discourses might ‘work’ to produce specific effects on practitioners and children as they are deployed and taken up in Scottish preschool education contexts. This analysis involves speculating about potential consequences for practitioners' and children's experiences and subjectivities. In conclusion, it is suggested that practitioners should critically engage with the curriculum, as uncritical acceptance of the discourses underpinning it could lead to practices that may have negative consequences. Furthermore, the article proposes that future research should investigate the ways in which the discourses privileged in the Curriculum for Excellence ‘health and wellbeing’ documentation are taken up and negotiated in Scottish preschool settings

Attentive Learning of Sequential Handwriting Movements: A Neural Network Model

Defense Advanced research Projects Agency and the Office of Naval Research (N00014-95-1-0409, N00014-92-J-1309); National Science Foundation (IRI-97-20333); National Institutes of Health (I-R29-DC02952-01)

Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles

We have made the first measurements of the virtual Compton scattering (VCS) process via the H$(e,e'p)\gamma$ exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the $W$-dependence at fixed $Q^2=1$ GeV$^2$, and for the $Q^2$-dependence at fixed $W$ near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed $Q^2$-dependence is smooth. The measured ratio of H$(e,e'p)\gamma$ to H$(e,e'p)\pi^0$ cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to Real Compton Scattering (RCS) at high energy and large angles, our VCS data at the highest $W$ (1.8-1.9 GeV) show a striking $Q^2$- independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.Comment: 20 pages, 8 figures. To appear in Phys.Rev.

Low Complexity Regularization of Linear Inverse Problems

Inverse problems and regularization theory is a central theme in contemporary signal processing, where the goal is to reconstruct an unknown signal from partial indirect, and possibly noisy, measurements of it. A now standard method for recovering the unknown signal is to solve a convex optimization problem that enforces some prior knowledge about its structure. This has proved efficient in many problems routinely encountered in imaging sciences, statistics and machine learning. This chapter delivers a review of recent advances in the field where the regularization prior promotes solutions conforming to some notion of simplicity/low-complexity. These priors encompass as popular examples sparsity and group sparsity (to capture the compressibility of natural signals and images), total variation and analysis sparsity (to promote piecewise regularity), and low-rank (as natural extension of sparsity to matrix-valued data). Our aim is to provide a unified treatment of all these regularizations under a single umbrella, namely the theory of partial smoothness. This framework is very general and accommodates all low-complexity regularizers just mentioned, as well as many others. Partial smoothness turns out to be the canonical way to encode low-dimensional models that can be linear spaces or more general smooth manifolds. This review is intended to serve as a one stop shop toward the understanding of the theoretical properties of the so-regularized solutions. It covers a large spectrum including: (i) recovery guarantees and stability to noise, both in terms of $\ell^2$-stability and model (manifold) identification; (ii) sensitivity analysis to perturbations of the parameters involved (in particular the observations), with applications to unbiased risk estimation ; (iii) convergence properties of the forward-backward proximal splitting scheme, that is particularly well suited to solve the corresponding large-scale regularized optimization problem

Planck 2015 results. XXVII. The Second Planck Catalogue of Sunyaev-Zeldovich Sources

We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest all-sky catalogue of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data-sets, and is the first SZ-selected cluster survey containing > $10^3$ confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the Y5R500 estimates are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires. the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical and X-ray data-sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under- luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02