1,326 research outputs found

    Why I Teach Introductory Courses

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    Noise

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75459/1/j.1096-0031.1999.tb00394.x.pd

    Metropolitan water intelligence systems completion report, phase III

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    Submitted to: U.S. Department of the Interior, Office of Water Resources Research.Series numbering taken from cover.June 1974.Grant no. 14-31-0001-9028

    Wasp genus Apoica

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    30 p. : ill. ; 26 cm.Includes bibliographical references (p. 28-29).A revision of the nocturnal social wasp genus, Apoica, is presented. The revision is based on a cladistic analysis of morphological, behavioral, and molecular characters of the nine nominal species. The subgenera Deuterapoica and Apoica are consistent with the phylogenetic results, and are thus retained. A new species, Apoica ellenae, whose phylogenetic position is uncertain, is described. A variant of A. albimacula from Peru is noted. This brings the total number of species in the genus to 10

    In Memoriam

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    Automated Generation of User Guidance by Combining Computation and Deduction

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    Herewith, a fairly old concept is published for the first time and named "Lucas Interpretation". This has been implemented in a prototype, which has been proved useful in educational practice and has gained academic relevance with an emerging generation of educational mathematics assistants (EMA) based on Computer Theorem Proving (CTP). Automated Theorem Proving (ATP), i.e. deduction, is the most reliable technology used to check user input. However ATP is inherently weak in automatically generating solutions for arbitrary problems in applied mathematics. This weakness is crucial for EMAs: when ATP checks user input as incorrect and the learner gets stuck then the system should be able to suggest possible next steps. The key idea of Lucas Interpretation is to compute the steps of a calculation following a program written in a novel CTP-based programming language, i.e. computation provides the next steps. User guidance is generated by combining deduction and computation: the latter is performed by a specific language interpreter, which works like a debugger and hands over control to the learner at breakpoints, i.e. tactics generating the steps of calculation. The interpreter also builds up logical contexts providing ATP with the data required for checking user input, thus combining computation and deduction. The paper describes the concepts underlying Lucas Interpretation so that open questions can adequately be addressed, and prerequisites for further work are provided.Comment: In Proceedings THedu'11, arXiv:1202.453

    Castes in neotropical swarm-founding wasps

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    24 p. : ill. ; 26 cm.Electronic version available in portable document format (PDF).Includes bibliographical references (p. 21-24).Reproductive castes are compared in species of swarming wasps representing all currently recognized genera of Epiponini (Polistinae). New morphometric data for nine measures of body parts and ovarian data are presented for 13 species. These are integrated with all similarly conducted available studies, giving a total of 30 species. Analysis reveals several syndromes relating reproductive and nonreproductive individuals: no meaningful distinction, physiological differences only, reproductives larger than nonreproductives with intermediate individuals present, reproductives different in shape from nonreproductives with no intermediates, and reproductives smaller in some aspects than nonreproductives. Distribution of these syndromes among species is consistent with phylogenetic relationships derived from other data. Optimizing these syndromes on the cladogram indicates that the basal condition of Epiponini is a casteless society that is not comparable to the primitively social genus Polistes where dominant queens control reproduction. Castes originate several times in Epiponini, with different results in different lineages. The best documented evolutionary sequence passes from casteless societies, to those with reproductives larger, to those with reproductives differing in shape from nonreproductives, to those with reproductives smaller in some measures. This sequence is consistent with Wheeler's theory of the origin of caste through developmental switches, and represents the most thorough test of that theory to date

    Environment and Past Land Use Together Predict Functional Diversity in a Temperate Forest

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    Environment and human land use both shape forest composition. Abiotic conditions sift tree species from a regional pool via functional traits that influence species’ suitability to the local environment. In addition, human land use can modify species distributions and change functional diversity of forests. However, it is unclear how environment and land use simultaneously shape functional diversity of tree communities. Land-use legacies are especially prominent in temperate forest landscapes that have been extensively modified by humans in the last few centuries. Across a 900-ha temperate deciduous forest in the northeastern United States, comprising a mosaic of different-aged stands due to past human land use, we used four key functional traits—maximum height, rooting depth, wood density, and seed mass—to examine how multiple environmental and land-use variables influenced species distributions and functional diversity. We sampled ~40,000 trees \u3e8 cm DBH within 485 plots totaling 137 ha. Species within plots were more functionally similar than expected by chance when we estimated functional diversity using all traits together (multi-trait), and to a lesser degree, with each trait separately. Multi-trait functional diversity was most strongly correlated with distance from the perennial stream, elevation, slope, and forest age. Environmental and land-use predictors varied in their correlation with functional diversities of the four individual traits. Landscape-wide change in abundances of individual species also correlated with both environment and land-use variables, but magnitudes of trait–environment interactions were generally stronger than trait interactions with land use. These findings can be applied for restoration and assisted regeneration of human-modified temperate forests by using traits to predict which tree species would establish well in relation to land-use history, topography, and soil conditions

    Paraphyly of Polybia

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    24 p. : ill. ; 26 cm.Includes bibliographical references (p. 22-24).A cladistic analysis of the subgenera of the paper wasp genus Polybia Lepeletier (Hymenoptera: Vespidae; Polistinae), and the other genera that construct phragmocyttarus nests, is presented. The results clearly indicate paraphyly of Polybia in terms of the genus Synoecoides Ducke. To remove the paraphyly, Synoecoides is reduced in rank, to a subgenus of Polybia, new synonymy
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