Compiling ER Specifications into Declarative Programs

This paper proposes an environment to support high-level database programming in a declarative programming language. In order to ensure safe database updates, all access and update operations related to the database are generated from high-level descriptions in the entity- relationship (ER) model. We propose a representation of ER diagrams in the declarative language Curry so that they can be constructed by various tools and then translated into this representation. Furthermore, we have implemented a compiler from this representation into a Curry program that provides access and update operations based on a high-level API for database programming.Comment: Paper presented at the 17th Workshop on Logic-based Methods in Programming Environments (WLPE2007

Preschool children's problem-solving interactions at computers and jigsaw puzzles

Preschool children's interactions while working on problem-solving tasks were investigated. In Study I, preschool children were observed working on learning games at a computer. Sharing, verbal and nonverbal instruction, and initiation of interaction were recorded. Sixty-three percent of the children's time at the computer was spent with a peer, and they often spontaneously shared and instructed each other.Age-related increases in time spent at the computer, as well as in self-initiation of interaction and sharing, were evident. No differences were found between boys' and girls' activities at the computer. In Study II, children were observed while working with jigsaw puzzles. In this context, children worked with peers just 7% of the time, and exhibited far fewer instances of cooperative interaction. The results of the research indicate that preschool children can engage in cooperative social interaction and instruction, and that under certain circumstances this activity may aid problem-solving. The research provides evidence that even children younger than school age can work effectively at computers. Moreover, the findings contradict common stereotypes about gender differences and social isolation from effects of computers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25718/1/0000275.pd

Near Infrared Spectra of Type Ia Supernovae

We report near infrared (NIR) spectroscopic observations of twelve ``Branch-normal'' Type Ia supernovae (SNe Ia) which cover the wavelength region from 0.8-2.5 microns. Our sample more than doubles the number of SNe Ia with published NIR spectra within three weeks of maximum light. The epochs of observation range from thirteen days before maximum light to eighteen days after maximum light. A detailed model for a Type Ia supernovae is used to identify spectral features. The Doppler shifts of lines are measured to obtain the velocity and, thus, the radial distribution of elements. The NIR is an extremely useful tool to probe the chemical structure in the layers of SNe Ia ejecta. This wavelength region is optimal for examining certain products of the SNe Ia explosion that may be blended or obscured in other spectral regions. We identify spectral features from MgII, CaII, SiII, FeII, CoII, NiII and possibly MnII. We find no indications for hydrogen, helium or carbon in the spectra. The spectral features reveal important clues about the physical characteristics of SNe Ia. We use the features to derive upper limits for the amount of unburned matter, to identify the transition regions from explosive carbon to oxygen burning and from partial to complete silicon burning, and to estimate the level of mixing during and after the explosion.Comment: 44 pages, 7 figures, 3 tables, accepted by Ap

Considerations for How to Rate CPV

The concentrator photovoltaic (CPV) industry is introducing multiple products into the marketplace, but, as yet, the community has not embraced a unified method for assessing a nameplate rating. The choices of whether to use 850, 900, or 1000 W/m2 for the direct-normal irradiance and whether to link the rating to ambient or cell temperature will affect how CPV modules are rated and compared with other technologies. This paper explores the qualitative and quantitative ramifications of these choices using data from two multi-junction CPV modules and two flat-plate modules

Lithospheric structure of an Archean craton and adjacent mobile belt revealed from 2-D and 3-D inversion of magnetotelluric data : example from southern Congo craton in northern Namibia

Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 118 (2013): 4378–4397, doi:10.1002/jgrb.50258.Archean cratons, and the stitching Proterozoic orogenic belts on their flanks, form an integral part of the Southern Africa tectonic landscape. Of these, virtually nothing is known of the position and thickness of the southern boundary of the composite Congo craton and the Neoproterozoic Pan-African orogenic belt due to thick sedimentary cover. We present the first lithospheric-scale geophysical study of that cryptic boundary and define its geometry at depth. Our results are derived from two-dimensional (2-D) and three-dimensional (3-D) inversion of magnetotelluric data acquired along four semiparallel profiles crossing the Kalahari craton across the Damara-Ghanzi-Chobe belts (DGC) and extending into the Congo craton. Two-dimensional and three-dimensional electrical resistivity models show significant lateral variation in the crust and upper mantle across strike from the younger DGC orogen to the older adjacent cratons. We find Damara belt lithosphere to be more conductive and significantly thinner than that of the adjacent Congo craton. The Congo craton is characterized by very thick (to depths of  250 km) and resistive (i.e., cold) lithosphere. Resistive upper crustal features are interpreted as caused by igneous intrusions emplaced during Pan-African magmatism. Graphite-bearing calcite marbles and sulfides are widespread in the Damara belt and account for the high crustal conductivity in the Central Zone. The resistivity models provide new constraints on the southern extent of the greater Congo craton and suggest that the current boundary drawn on geological maps needs revision and that the craton should be extended further south.The SAMTEX consortiummembers (Dublin Institute for Advanced Studies, Woods Hole Oceanographic Institution, Council for Geoscience (South Africa), De Beers Group Services, The University of the Witwatersrand, Geological Survey of Namibia, Geological Survey of Botswana, Rio Tinto Mining and Exploration, BHP Billiton, Council for Scientific and Industrial Research (South Africa), and ABB Sweden) are thanked for their funding and logistical support during the four phases of data acquisition. This work is also supported by research grants from the National Science Foundation (EAR-0309584 and EAR-0455242 through the Continental Dynamics Program to R. L. Evans), the Department of Science and Technology, South Africa, and Science Foundation of Ireland (grant 05/RFP/ GEO001to A. G. Jones).2014-02-0

Investigation into Spectral Parameters as they Impact CPV Module Performance

The CPV industry is well aware that performance of triple junction cells depends on spectral conditions but there is a lack of data quantifying this spectral dependence at the module level. This paper explores the impact of precipitable water vapor, aerosol optical depth (AOD), and optical air mass on multiple CPV module technologies on-sun in Golden, CO

Using Atom Interferometery to Search for New Forces

Atom interferometry is a rapidly advancing field and this Letter proposes an experiment based on existing technology that can search for new short distance forces. With current technology it is possible to improve the sensitivity by up to a factor of 10^2 and near-future advances will be able to rewrite the limits for forces with ranges from 100 um to 1 km.Comment: 5 pages, 2 figure