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31.
Muller Jeff M.; Brunelli Susan A; Moore Holly; Myers Michael M.; Shair Harry N. 《Canadian Metallurgical Quarterly》2005,119(5):1384
Although dopamine is necessary for mammalian adult pair-bond formation and maternal behavior, its function in infant social behavior and attachment has been less thoroughly explored. The vocalization rate of an isolated rat pup is influenced by recent social contact. Interactions with the dam potentiate vocalization rate. Interactions with littermates or adult males do not. Systemic administration of the D2-family agonist quinpirole specifically blocked maternal potentiation at doses that did not alter vocalization rate in an isolation prior to dam contact. This result was not explained by quinpirole's effects on body temperature or locomotion. The results are consistent with a role for dopamine in infant social behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
32.
Kai Chen Stephen R. Schach Liguo Yu Jeff Offutt Gillian Z. Heller 《Empirical Software Engineering》2004,9(3):197-210
A recent editorial in Empirical Software Engineering suggested that open-source software projects offer a great deal of data that can be used for experimentation. These data not only include source code, but also artifacts such as defect reports and update logs. A common type of update log that experimenters may wish to investigate is the ChangeLog, which lists changes and the reasons for which they were made. ChangeLog files are created to support the development of software rather than for the needs of researchers, so questions need to be asked about the limitations of using them to support research. This paper presents evidence that the ChangeLog files provided at three open-source web sites were incomplete. We examined at least three ChangeLog files for each of three different open-source software products, namely, GNUJSP, GCC-g++, and Jikes. We developed a method for counting changes that ensures that, as far as possible, each individual ChangeLog entry is treated as a single change. For each ChangeLog file, we compared the actual changes in the source code to the entries in the ChangeLog> file and discovered significant omissions. For example, using our change-counting method, only 35 of the 93 changes in version 1.11 of Jikes appear in the ChangeLog file—that is, over 62% of the changes were not recorded there. The percentage of omissions we found ranged from 3.7 to 78.6%. These are significant omissions that should be taken into account when using ChangeLog files for research. Before using ChangeLog files as a basis for research into the development and maintenance of open-source software, experimenters should carefully check for omissions and inaccuracies. 相似文献
33.
Laurent Jeff; Catanzaro Salvatore J.; Joiner Thomas E. Jr. 《Canadian Metallurgical Quarterly》2004,16(4):373
Considerable empirical support exists for the positive affect and negative affect components of the tripartite model of anxiety and depression proposed by L. A. Clark and D. Watson (1991); however, less attention has been paid to the physiological hyperarousal component of the model. The development of the Physiological Hyperarousal Scale for Children (PH-C; J. Laurent, S. J. Catanzaro, & T. E. Joiner Jr., 1995) is described. The psychometric properties of items are examined using students in Grades 6-12 (N = 398). Initial scale validation includes a joint factor analysis with the Positive and Negative Affect Scale for Children (PANAS-C; J. Laurent et al., 1999; J. Laurent, K. Potter, & S. J. Catanzaro, 1994). The relationship between the PH-C and existing measures that tap related constructs is examined. Together, the PH-C and PANAS-C provide a means to assess tripartite model constructs useful in differentiating anxiety and depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
34.
How does snow's anisotropic directional reflectance affect the mapping of snow properties from imaging spectrometer data? This sensitivity study applies two spectroscopy models to synthetic images of the spectral hemispherical-directional reflectance factor (HDRF) with prescribed snow-covered area and snow grain size. The MEMSCAG model determines both sub-pixel snow-covered area and the grain size of the fractional snow cover. The Nolin/Dozier model analyzes the ice absorption feature that spans wavelength λ≅1.03 μm to estimate snow grain radius when the pixel is fully snow-covered. Retrievals of subpixel snow-covered area with MEMSCAG are progressively more sensitive to the HDRF as grain size decreases, solar zenith angle increases, and fractional snow cover increases. The model overestimates snow cover in the forward reflectance angles by up to +20% and underestimates it in the backward reflectance angles by as much as −15%. Grain size retrievals from both MEMSCAG and Nolin/Dozier are more sensitive to anisotropy as grain size and solar zenith angle increase. MEMSCAG retrievals of grain size are insensitive to snow-covered area. The largest inferred grain sizes occur around a peak in the backward reflectance angles and the smallest generally occur at the largest view angles in the forward direction. Retrievals of albedo from MEMSCAG and Nolin/Dozier are similarly sensitive to anisotropy, with albedo errors up to 5% for a 30° solar zenith angle and up to 10% at 60°. The albedo differences between the two models are less than 0.015 for all grain sizes and solar zenith angles. 相似文献
35.
Emotion theorists have long debated whether valence, which ranges from pleasant to unpleasant states, is an irreducible aspect of the experience of emotion or whether positivity and negativity are separable in experience. If valence is irreducible, it follows that people cannot feel happy and sad at the same time. Conversely, if positivity and negativity are separable, people may be able to experience such mixed emotions. The authors tested several alternative interpretations for prior evidence that happiness and sadness can co-occur in bittersweet situations (i.e., those containing both pleasant and unpleasant aspects). One possibility is that subjects who reported mixed emotions merely vacillated between happiness and sadness. The authors tested this hypothesis in Studies 1–3 by asking subjects to complete online continuous measures of happiness and sadness. Subjects reported more simultaneously mixed emotions during a bittersweet film clip than during a control clip. Another possibility is that subjects in earlier studies reported mixed emotions only because they were explicitly asked whether they felt happy and sad. The authors tested this hypothesis in Studies 4–6 with open-ended measures of emotion. Subjects were more likely to report mixed emotions after the bittersweet clip than the control clip. Both patterns occurred even when subjects were told that they were not expected to report mixed emotions (Studies 2 and 5) and among subjects who did not previously believe that people could simultaneously feel happy and sad (Studies 3 and 6). These results provide further evidence that positivity and negativity are separable in experience. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
36.
Shape deformation in continuous map generalization 总被引:2,自引:0,他引:2
Jeff Danciger Satyan L. Devadoss John Mugno Don Sheehy Rachel Ward 《GeoInformatica》2009,13(2):203-221
Given a collection of regions on a map, we seek a method of continuously altering the regions as the scale is varied. This
is formalized and brought to rigor as well-defined problems in homotopic deformation. We ask the regions to preserve topology,
area-ratios, and relative position as they change over time. A solution is presented using differential methods and computational
geometric techniques. Most notably, an application of this method is used to provide an algorithm to obtain cartograms.
Jeff Danciger Jeffrey received his undergraduate degree from the College of Creative Studies at UCSB in mathematics and physics. He is currently working on his Ph.D. in mathematics at Stanford University. His research interests include low dimensional topology and geometric analysis. Satyan L. Devadoss is an Associate Professor of Mathematics at Williams College. His research interests lie in the interplay between topology and geometry, notably in applications to theoretical physics (moduli spaces and string theory) and computer science (cartography and polytopes). John Mugno received his undergraduate degree from Williams College and is currently continuing his studies in mathematics at the University of Maryland. His areas of interest include combinatorics and topology. Don Sheehy received his undergraduate degree in Princeton University and is currently pursuing a PhD in Computer Science at Carnegie Mellon University. His research focuses on computational geometry algorithms for meshing. Rachel Ward received her undergraduate degree at the University of Texas at Austin. She is now a PhD student at Princeton University in the Program in Applied and Computational Mathematics. Her current work is in the area of compressed sensing, combining tools from computational harmonic analysis, probability, and optimization theory. 相似文献
Rachel WardEmail: |
Jeff Danciger Jeffrey received his undergraduate degree from the College of Creative Studies at UCSB in mathematics and physics. He is currently working on his Ph.D. in mathematics at Stanford University. His research interests include low dimensional topology and geometric analysis. Satyan L. Devadoss is an Associate Professor of Mathematics at Williams College. His research interests lie in the interplay between topology and geometry, notably in applications to theoretical physics (moduli spaces and string theory) and computer science (cartography and polytopes). John Mugno received his undergraduate degree from Williams College and is currently continuing his studies in mathematics at the University of Maryland. His areas of interest include combinatorics and topology. Don Sheehy received his undergraduate degree in Princeton University and is currently pursuing a PhD in Computer Science at Carnegie Mellon University. His research focuses on computational geometry algorithms for meshing. Rachel Ward received her undergraduate degree at the University of Texas at Austin. She is now a PhD student at Princeton University in the Program in Applied and Computational Mathematics. Her current work is in the area of compressed sensing, combining tools from computational harmonic analysis, probability, and optimization theory. 相似文献
37.
Yazeed Alaskar Shamsul Arafin Darshana Wickramaratne Mark A. Zurbuchen Liang He Jeff McKay Qiyin Lin Mark S. Goorsky Roger K. Lake Kang L. Wang 《Advanced functional materials》2014,24(42):6629-6638
Van der Waals growth of GaAs on silicon using a two‐dimensional layered material, graphene, as a lattice mismatch/thermal expansion coefficient mismatch relieving buffer layer is presented. Two‐dimensional growth of GaAs thin films on graphene is a potential route towards heteroepitaxial integration of GaAs on silicon in the developing field of silicon photonics. Hetero‐layered GaAs is deposited by molecular beam epitaxy on graphene/silicon at growth temperatures ranging from 350 °C to 600 °C under a constant arsenic flux. Samples are characterized by plan‐view scanning electron microscopy, atomic force microscopy, Raman microscopy, and X‐ray diffraction. The low energy of the graphene surface and the GaAs/graphene interface is overcome through an optimized growth technique to obtain an atomically smooth low temperature GaAs nucleation layer. However, the low adsorption and migration energies of gallium and arsenic atoms on graphene result in cluster‐growth mode during crystallization of GaAs films at an elevated temperature. In this paper, we present the first example of an ultrasmooth morphology for GaAs films with a strong (111) oriented fiber‐texture on graphene/silicon using quasi van der Waals epitaxy, making it a remarkable step towards an eventual demonstration of the epitaxial growth of GaAs by this approach for heterogeneous integration. 相似文献
38.
通过与其它传感技术的对比,简要分析了激光视觉在焊接生产中得到成功应用的原因。分析了早期激光视觉系统的特征和当时面临的挑战。介绍了Servo-Robot激光视觉的关键技术和已取得的显著进步,阐述了集成激光视觉的移动式便携焊接机器人和激光视觉在焊缝质量检测中的应用。展望了激光视觉系统的未来和智能视觉在提高机器人性能方面发展的显著进步,包括改进机器人人工示教、离线编程及视觉辅助机器人示教。 相似文献
39.
40.
Jeff R. Wright Steven C. Egly Hugh W. Gallivan 《Civil Engineering and Environmental Systems》2013,30(1):16-21
The focus of this research was the development of a model to address the problem of reassigning summer construction workers to winter snow and ice removal teams in an efficient and cost-effective manner. The model is a multi-objective integer program that can generate the complete and precise trade-off curve between the objectives of minimizing total distance that the reassigned workforce must travel from their respective homes to one of many site locations, and minimizing the maximum distance that any one worker must travel. System constraints include demand requirements for workers at each site and the limited availability of state-owned vehicles that may be issued to workers assigned to remote sites. Details of the model structure and solution procedure are presented together with the results of an actual application. 相似文献