Program representation size in an intermediate language with intersection and union types

The CIL compiler for core Standard ML compiles whole programs using a novel typed intermediate language (TIL) with intersection and union types and flow labels on both terms and types. The CIL term representation duplicates portions of the program where intersection types are introduced and union types are eliminated. This duplication makes it easier to represent type information and to introduce customized data representations. However, duplication incurs compile-time space costs that are potentially much greater than are incurred in TILs employing type-level abstraction or quantification. In this paper, we present empirical data on the compile-time space costs of using CIL as an intermediate language. The data shows that these costs can be made tractable by using sufficiently fine-grained flow analyses together with standard hash-consing techniques. The data also suggests that non-duplicating formulations of intersection (and union) types would not achieve significantly better space complexity.National Science Foundation (CCR-9417382, CISE/CCR ESS 9806747); Sun grant (EDUD-7826-990410-US); Faculty Fellowship of the Carroll School of Management, Boston College; U.K. Engineering and Physical Sciences Research Council (GR/L 36963, GR/L 15685

The interaction of gibberellic acid and 2-(chloroethyl) trimethyl ammonium chloride on fruit cluster development in Vitis vinifera L.

The effects of applications of GA and CCC in factorial combinations and at different stages of development were measured on reproductive development of five cultivars of Vitis vinifera: Doradillo and Muscat (seeded), Sultana (stenospermocarpic), and Cape Currant and Zante Currant (parthenocarpic). The effect of GA on fruit set varied with concentration, stage of development when applied, and the cultivar, that is whether seeded, stenospermocarpic, or parthenocarpic. Set was decreased in the parthenocarpic cultivars by GA applied before anthesis; other timings were without effect. On Sultana, set was decreased by GA applied at anthesis but was increased by earlier or later applications. With the seeded cultivars, GA reduced the number of seeded berries but increased the number of seedless berries, the net effect being usually an increase. The application of CCC two weeks. before anthesis generally increased set. The amount of seed development also influenced the effect of GA on berry fresh weight; seeded berries were unaffected but seedless berries were usually enlarged. The enlargement was greatest in parthenocarpic berries especially when treated at anthesis. On stenospermocarpic berries, treatment two weeks after anthesis had the greatest effect. CCC reduced berry size whether applied before or after anthesis; the reductions ranged from 2 to 20 per cent.GA increased the length/width ratio of berries, particularly when applied at anthesis, but the amount of change depended on the cultivar. CCC reduced the length/width ratio of Sultana berries. The effects of GA and CCC on rachis elongation were also opposite: GA increased the length of the rachis and pedicel, particularly if applied before anthesis; CCC reduced their length.There were few instances where GA and CCC interacted significantly; their effects within the concentration ranges chosen were generally additive.Der Einfluß von Gibberellinsäure und CCC auf die Traubenentwicklung bei Vitis vinifera L.Der Einfluß von Gibberellinsäure (GS)- und CCC-Gaben in faktorieller Kombination und in verschiedenen Entwicklungsphasen auf die generative Entwicklung der fünf Vitis vinifera-Sorten Doradillo und Muskat (samenhaltig), Sultana (stenospermokarp), Cape Currant und Zante Currant (parthenokarp) wurde gemessen. Der Einfluß der GS auf den Fruchtansatz hing von der Konzentration, dem Entwicklungsstadium zur Zeit der Applikation und von der Sorte ab, d. h. ob samenhaltig, stenospermokarp oder parthenokarp. Vor der Anthesis angewendet, verminderte GS den Fruchtansatz; spätere Anwendungen waren ohne Wirkung. Bei Sultana verminderte GS den Fruchtansatz, wenn sie zur Blütezeit, und erhöhte ihn, wenn sie vorher oder nachher appliziert wurde. Bei den samenhaltigen Sorten verminderte GS die Zahl der samenhaltigen und erhöhte die der samenlosen Beeren; die Gesamtzahl der Beeren war gewöhnlich vergrößert. Die Anwendung von CCC zwei Wochen vor dem Blühen erhöhte allgemein den Fruchtansatz.Über die Samenentwicklung beeinflußte GS auch das Frischgewicht der Beeren; samenhaltige Beeren ließen keine Wirkung erkennen, während samenlose meistens vergrößert waren, und zwar am stärksten bei parthenokarpen Beeren, besonders nach Behandlung während der Anthesis. Bei stenospermokarpen Beeren hatte die zwei Wochen nach der Blütezeit applizierte GS die größte Wirkung. CCC, vor oder nach dem Aufblühen angewendet, verminderte die Beerengröße; der Rückgang betrug 2-20%. Durch GS wurde - sortenabhängig - das Verhältnis Länge/Breite der Beeren vergrößert, besonders bei Anwendung während der Anthesis. CCC verminderte dieses Verhältnis bei Sultana-Beeren. Auch das Wachstum des Traubenstieles wurde durch GS und CCC gegensätzlich beeinflußt; GS förderte das Längenwachstum von Traubenund Beerenstielen, besonders bei Anwendung vor der Blüte; CCC verminderte es. In einigen Fällen beeinflußten sich GS und CCC gegenseitig signifikant; im allgemeinen wurden hierdurch bei den verwendeten Konzentrationen ihre Wirkungen gesteigert

Gibberellic acid, chlorocholine chloride and yield increases in Zante currant

GA and CCC additively increased yield of Zante currant fruit. GA induced an increase in berry size (weight and volume) which was unaffected by CCC, while CCC offset to an appreciable extent the reduction in berry number associated with low concentrations of GA

Sensitivity of Global Modeling Initiative chemistry and transport model simulations of radon-222 and lead-210 to input meteorological data

International audienceWe have used the Global Modeling Initiative chemistry and transport model to simulate the radionuclides radon-222 and lead-210 using three different sets of input meteorological information: 1. Output from the Goddard Space Flight Center Global Modeling and Assimilation Office GEOS-STRAT assimilation; 2. Output from the Goddard Institute for Space Studies GISS II' general circulation model; and 3. Output from the National Center for Atmospheric Research MACCM3 general circulation model. We intercompare these simulations with observations to determine the variability resulting from the different meteorological data used to drive the model, and to assess the agreement of the simulations with observations at the surface and in the upper troposphere/lower stratosphere region. The observational datasets we use are primarily climatologies developed from multiple years of observations. In the upper troposphere/lower stratosphere region, climatological distributions of lead-210 were constructed from ~25 years of aircraft and balloon observations compiled into the US Environmental Measurements Laboratory RANDAB database. Taken as a whole, no simulation stands out as superior to the others. However, the simulation driven by the NCAR MACCM3 meteorological data compares better with lead-210 observations in the upper troposphere/lower stratosphere region. Comparisons of simulations made with and without convection show that the role played by convective transport and scavenging in the three simulations differs substantially. These differences may have implications for evaluation of the importance of very short-lived halogen-containing species on stratospheric halogen budgets

Impact of stratospheric aircraft on calculations of nitric acid trihydrate cloud surface area densities using NMC temperatures and 2D model constituent distributions

A parameterization of NAT (nitric acid trihydrate) clouds is developed for use in 2D models of the stratosphere. The parameterization uses model distributions of HNO3 and H2O to determine critical temperatures for NAT formation as a function of latitude and pressure. National Meteorological Center temperature fields are then used to determine monthly temperature frequency distributions, also as a function of latitude and pressure. The fractions of these distributions which fall below the critical temperatures for NAT formation are then used to determine the NAT cloud surface area density for each location in the model grid. By specifying heterogeneous reaction rates as functions of the surface area density, it is then possible to assess the effects of the NAT clouds on model constituent distributions. We also consider the increase in the NAT cloud formation in the presence of a fleet of stratospheric aircraft. The stratospheric aircraft NO(x) and H2O perturbations result in increased HNO3 as well as H2O. This increases the probability of NAT formation substantially, especially if it is assumed that the aircraft perturbations are confined to a corridor region

Transporting Stratospheric Water Vapor in the GMI Combo Model

I discuss the implementation of an H2O transport scheme in the Global Modeling Initiative (GMI) model

Modelling the preferences of students for alternative assignment designs using the Discrete Choice Experiment methodology

This paper outlines how a discrete choice experiment (DCE) can be used to learn more about how students are willing to trade off various features of assignments such as the nature and timing of feedback and the method used to submit assignments. A DCE identifies plausible levels of the key attributes of a good or service and then presents the respondent with alternative bundles of these attributes and their levels and asks the respondent to choose between particular bundles. We report results from a DCE we conducted with undergraduate business students regarding their preferences for assignment systems. We find that the most important features of assignments are how relevant the assignments are for exam preparation and the nature of the feedback that students receive. We also find that students generally prefer online to paper assignments. We argue that the DCE approach has a lot of potential in education research. Accessed 4,497 times on https://pareonline.net from November 13, 2014 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right

Simulation of Long Lived Tracers Using an Improved Empirically Based Two-Dimensional Model Transport Algorithm

We have developed a new empirically-based transport algorithm for use in our GSFC two-dimensional transport and chemistry model. The new algorithm contains planetary wave statistics, and parameterizations to account for the effects due to gravity waves and equatorial Kelvin waves. As such, this scheme utilizes significantly more information compared to our previous algorithm which was based only on zonal mean temperatures and heating rates. The new model transport captures much of the qualitative structure and seasonal variability observed in long lived tracers, such as: isolation of the tropics and the southern hemisphere winter polar vortex; the well mixed surf-zone region of the winter sub-tropics and mid-latitudes; the latitudinal and seasonal variations of total ozone; and the seasonal variations of mesospheric H2O. The model also indicates a double peaked structure in methane associated with the semiannual oscillation in the tropical upper stratosphere. This feature is similar in phase but is significantly weaker in amplitude compared to the observations. The model simulations of carbon-14 and strontium-90 are in good agreement with observations, both in simulating the peak in mixing ratio at 20-25 km, and the decrease with altitude in mixing ratio above 25 km. We also find mostly good agreement between modeled and observed age of air determined from SF6 outside of the northern hemisphere polar vortex. However, observations inside the vortex reveal significantly older air compared to the model. This is consistent with the model deficiencies in simulating CH4 in the northern hemisphere winter high latitudes and illustrates the limitations of the current climatological zonal mean model formulation. The propagation of seasonal signals in water vapor and CO2 in the lower stratosphere showed general agreement in phase, and the model qualitatively captured the observed amplitude decrease in CO2 from the tropics to midlatitudes. However, the simulated seasonal amplitudes were attenuated too rapidly with altitude in the tropics. Overall, the simulations with the new transport formulation are in substantially better agreement with observations compared with our previous model transport

Processes controlling the seasonal variations of 210Pb and 7Be at the Mt. Cimone WMO-GAW global station, Italy: A model analysis

We apply the Global Modeling Initiative (GMI) chemistry and transport model 14 driven by the NASA\u2019s MERRA assimilated meteorological data to simulate the seasonal variations of two radionuclide aerosol tracers (terrigenous 210Pb and cosmogenic 7 15 Be) at the 16 WMO-GAW station of Mt. Cimone (44\ub012\u2019 N, 10\ub042\u2019 E, 2165 m asl, Italy), which is 17 representative of free-tropospheric conditions most of the year, during 2005 with an aim to 18 understand the roles of transport and precipitation scavenging processes in controlling their 19 seasonality. The total precipitation field in the MERRA data set is evaluated with the Global 20 Precipitation Climatology project (GPCP) observations, and a generally good agreement is found. The model reproduces reasonably the observed seasonal pattern of 210 21 Pb concentrations, characterized by a wintertime minimum due to lower 222 22 Rn emissions and weaker uplift from the boundary layer and summertime maxima resulting from strong convection over the continent. The observed seasonal behavior of 7Be concentrations shows a winter minimum, a summer maximum, and a secondary spring maximum. The model captures the observed 7Be 4 pattern in winter-spring, which is linked to the larger stratospheric influence during spring. However, the model tends to underestimate the observed 7Be concentrations in summer, 6 partially due to the sensitivity to spatial sampling in the model. Model sensitivity experiments 7 indicate a dominant role of precipitation scavenging (versus dry deposition and convection) in controlling the seasonality of 210Pb and 7 Be concentrations at Mt. Cimone

Transition from electron accumulation to depletion at InGaN surfaces

The composition dependence of the Fermi-level pinning at the oxidized (0001) surfaces of n-type InxGa1−xN films (0<=x<=1) is investigated using x-ray photoemission spectroscopy. The surface Fermi-level position varies from high above the conduction band minimum (CBM) at InN surfaces to significantly below the CBM at GaN surfaces, with the transition from electron accumulation to depletion occurring at approximately x=0.3. The results are consistent with the composition dependence of the band edges with respect to the charge neutrality level