2,296 research outputs found

    Rifting and Mafic Magmatism in the Hebridean Basins

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    Acknowledgements and Funding Research in the BPIP was supported by NERC grant GR9/1581, and the Carnegie Trust for the Universities of Scotland. H. Rollinson and E. Gazel are thanked for helpful and constructive criticisms, particularly of the modelling aspects of the paper, and T. Rooney is thanked for invaluable scientific and editorial assistance.Peer reviewedPostprin

    Adapting the Access Northwind Database to Support a Database Course

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    A common problem encountered when teaching database courses is that few large illustrative databases exist to support teaching and learning. Most database textbooks have small ‘toy’ databases that are chapter objective specific, and thus do not support application over the complete domain of design, implementation and management concepts across a single database. The Northwind Traders sample database is available by Microsoft for download and use in Microsoft Access, and illustrates transactional processing for a fictitious company that imports (purchases) and exports (sells) specialty foods from around the world. The database contains sample tables, queries, forms, reports, Macros, VBA Class Objects, functions and modules, and other database features. Although the primary purpose for the database is to serve as an illustrative design template for students and practitioners, unfortunately the database and business processes are largely undocumented. This paper attempts to more completely document the business processes, including establishing business rules, describing relationships and participations, and discusses some problems with the existing design. Following understanding of the database and associated business processes, this paper can be used as both a teaching tool and a guide for practitioners using the Northwind Traders sample database as a design template. Additionally, it has been used successfully to introduce the concept of business processes and mapping them in an underlying database in introductory ERP courses

    Mapping Relational Algebra Operators into SQL Queries: A Database Case Study

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    Relational algebra operators and mapping to resulting structured query language (SQL) queries are among the most important concepts and skills for students taking a course in database design and implementation, especially those majoring in IS/IT. The most typical relational algebra operators mapped to foundational SQL include unions and intersections, as well as other relational operators applied to these operators, including differences and various joins. Unfortunately, few textbooks or external resources provide ample opportunity for students to apply the full set of most common relational algebra operators mapped to resulting SQL over a single unified case. Most database textbooks exemplify each separate relational algebra construct to a single, sparse (although visually-stimulating) example, wherein the full set of operators is not near fully exemplified. This paper presents an overview of a case example that exemplifies and maps a more complete set of relational algebra operators in related SQL operations across a unified case. The case replicates the author’s real experience in building a database solution for an online retailer of sporting goods products. It is hoped that this case example will help database teachers more effectively teach relational algebra concepts, the subsequent mapping to SQL, and resulting queries, as well as provide students a greater understanding of relational algebra and mapping to SQL. Although the case example is exemplified in Microsoft Access 2010/2013, the case can be modified and presented using any relational database management system (RDBMS)

    The Application of the United States Hazardous Waste Cleanup Laws in the Canada-U.S. Context

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    Chaotic maps and pattern recognition - the XOR problem

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    In this report, we describe a novel application of the Baker's map. We demonstrate that the chaotic properties of this map can be used to implement basic operations in Boolean logic. This observation leads naturally to the possibility of new computational models and implementations for conventional computational systems. Here we show that by considering the variation of the fractal dimension of its attractor, and using varying parameter values as inputs, the generalised Baker's map can be used as a natural exclusive OR (XOR) gate. Further, this map can also be used to create other logical functions such as the AND gate. The efficacy of our results are demonstrated by means of a concrete application; namely by designing, to the best of our knowledge, for the frst time, a half-adder that is constructed entirely by utilising chaotic dynamics

    Beyond Shape: How You Learn about Objects Affects How They Are Represented in Visual Cortex

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    Background: Experience can alter how objects are represented in the visual cortex. But experience can take different forms. It is unknown whether the kind of visual experience systematically alters the nature of visual cortical object representations. Methodology/Principal Findings: We take advantage of different training regimens found to produce qualitatively different types of perceptual expertise behaviorally in order to contrast the neural changes that follow different kinds of visual experience with the same objects. Two groups of participants went through training regimens that required either subordinate-level individuation or basic-level categorization of a set of novel, artificial objects, called ‘‘Ziggerins’’. fMRI activity of a region in the right fusiform gyrus increased after individuation training and was correlated with the magnitude of configural processing of the Ziggerins observed behaviorally. In contrast, categorization training caused distributed changes, with increased activity in the medial portion of the ventral occipito-temporal cortex relative to more lateral areas. Conclusions/Significance: Our results demonstrate that the kind of experience with a category of objects can systematically influence how those objects are represented in visual cortex. The demands of prior learning experience therefore appear t

    The California-Kepler Survey. II. Precise Physical Properties of 2025 Kepler Planets and Their Host Stars

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    We present stellar and planetary properties for 1305 Kepler Objects of Interest (KOIs) hosting 2025 planet candidates observed as part of the California-Kepler Survey. We combine spectroscopic constraints, presented in Paper I, with stellar interior modeling to estimate stellar masses, radii, and ages. Stellar radii are typically constrained to 11%, compared to 40% when only photometric constraints are used. Stellar masses are constrained to 4%, and ages are constrained to 30%. We verify the integrity of the stellar parameters through comparisons with asteroseismic studies and Gaia parallaxes. We also recompute planetary radii for 2025 planet candidates. Because knowledge of planetary radii is often limited by uncertainties in stellar size, we improve the uncertainties in planet radii from typically 42% to 12%. We also leverage improved knowledge of stellar effective temperature to recompute incident stellar fluxes for the planets, now precise to 21%, compared to a factor of two when derived from photometry.Comment: 13 pages, 4 figures, 4 tables, accepted for publication in AJ; full versions of tables 3 and 4 are include

    The California-Kepler Survey. I. High Resolution Spectroscopy of 1305 Stars Hosting Kepler Transiting Planets

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    The California-Kepler Survey (CKS) is an observational program to improve our knowledge of the properties of stars found to host transiting planets by NASA's Kepler Mission. The improvement stems from new high-resolution optical spectra obtained using HIRES at the W. M. Keck Observatory. The CKS stellar sample comprises 1305 stars classified as Kepler Objects of Interest, hosting a total of 2075 transiting planets. The primary sample is magnitude-limited (Kp < 14.2) and contains 960 stars with 1385 planets. The sample was extended to include some fainter stars that host multiple planets, ultra short period planets, or habitable zone planets. The spectroscopic parameters were determined with two different codes, one based on template matching and the other on direct spectral synthesis using radiative transfer. We demonstrate a precision of 60 K in effective temperature, 0.10 dex in surface gravity, 0.04 dex in [Fe/H], and 1.0 km/s in projected rotational velocity. In this paper we describe the CKS project and present a uniform catalog of spectroscopic parameters. Subsequent papers in this series present catalogs of derived stellar properties such as mass, radius and age; revised planet properties; and statistical explorations of the ensemble. CKS is the largest survey to determine the properties of Kepler stars using a uniform set of high-resolution, high signal-to-noise ratio spectra. The HIRES spectra are available to the community for independent analyses.Comment: 20 pages, 19 figures, accepted for publication in AJ; a full version of Table 5 is included as tab_cks.csv and tab_cks.te

    How Uncertain Are Solar Neutrino Predictions?

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    Solar neutrino fluxes and sound speeds are calculated using a systematic reevaluation of nuclear fusion rates. The largest uncertainties are identified and their effects on the solar neutrino fluxes are estimated.Comment: LaTeX file, 12 pages including three postscript figures. To be published in Phys. Lett. B. One reference correcte
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