1,182,139 research outputs found

    Cognitive constraints and island effects

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    Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that nonstructural manipulations that leave island structures intact can radically alter judgments of island violations. We argue here, building on work by Paul Deane, Robert Kluender, and others, that processing factors have the potential to account for this otherwise unexplained variation in acceptability judgments. We report the results of self-paced reading experiments and controlled acceptability studies that explore the relationship between processing costs and judgments of acceptability. In each of the three self-paced reading studies, the data indicate that the processing cost of different types of island violations can be significantly reduced to a degree comparable to that of nonisland filler-gap constructions by manipulating a single nonstructural factor. Moreover, this reduction in processing cost is accompanied by significant improvements in acceptability. This evidence favors the hypothesis that island-violating constructions involve numerous processing pressures that aggregate to drive processing difficulty above a threshold, resulting in unacceptability. We examine the implications of these findings for the grammar of filler-gap dependencies

    Island formation without attractive interactions

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    We show that adsorbates on surfaces can form islands even if there are no attractive interactions. Instead strong repulsion between adsorbates at short distances can lead to islands, because such islands increase the entropy of the adsorbates that are not part of the islands. We suggest that this mechanism cause the observed island formation in O/Pt(111), but it may be important for many other systems as well.Comment: 11 pages, 4 figure

    Self-assembled germanium islands grown on (001) silicon substrates by low-pressure chemical vapor deposition

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    The time evolution of self-assembled Ge islands, during low-pressure chemical vapor deposition (LPCVD) of Ge on Si at 650 Deg C using high growth rates, has been investigated by atomic force microscopy, transmission electron microscopy, and Rutherford backscattering spectrometry. We have found three different island structures The smallest islands are "lens-shaped" and characterized by a rather narrow size distribution, ~4nm high and ~20nm wide. Next to form are a distinct population of multifaceted "dome shaped" islands, up to 25nm high and 80-150 nm wide. Finally, the largest islands that form are square-based truncated pyramids with a very narrow size distribution ~50nm high and ~250nm wide. The pyramidal islands normally seen in the intermediate size range (~150nm) are not observed. The small lens-shaped islands appear to be defect free, while some of the multifaceted islands as well as all the large truncated pyramids contain misfit dislocations. The existence of multifaceted islands, in the size range where multifaceted "dome shaped" islands have previously been reported, is attributed to the high growth rate used. Furthermore, under the growth conditions used, the truncated-pyramid-shaped islands are characterized by a very narrow size distribution

    Prepyramid-to-pyramid transition of SiGe islands on Si(001)

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    The morphology of the first three-dimensional islands appearing during strained growth of SiGe alloys on Si(001) was investigated by scanning tunneling microscopy. High resolution images of individual islands and a statistical analysis of island shapes were used to reconstruct the evolution of the island shape as a function of size. As they grow, islands undergo a transition from completely unfacetted rough mounds (prepyramids) to partially {105} facetted islands and then they gradually evolve to {105} facetted pyramids. The results are in good agreement with the predictions of a recently proposed theoretical model

    Improving the 14c dating of marine shells from the Canary Islands for constructing more reliable and accurate chronologies

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    Radiocarbon dating of closely associated marine mollusk shells and terrestrial material (charred wood or bone) collected from archaeological contexts on Tenerife and Fuerteventura islands allowed us to quantify the marine C-14 reservoir effect (Delta R) around the Canary Archipelago. Coastal Fuerteventura has a positive weighted mean Delta R value of +185 +/- 30 C-14 yr, while for Tenerife a range of negative and positive values was obtained, resulting in a Delta R weighted mean value of 0 +/- 35 C-14 yr. These values are in accordance with the hydrodynamic system present off the Canary Islands characterized by a coastal upwelling regime that affects the eastern islands (Fuerteventura and Lanzarote) but not the other islands of the archipelago, namely Tenerife. Because of this oceanographic pattern, we recommend the extrapolation of these results to the remaining islands of the archipelago, i.e. the first value must be used for the eastern islands, while for the central and western islands the acceptable Delta R value is 0 +/- 35 C-14 yr

    String Islands

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    We discuss string theories with small numbers of non-compact moduli and describe constructions of string theories whose low-energy limit is described by various pure supergravity theories. We also construct a D=4,N=4 compactification of type II string theory with 34 vector fields.Comment: An erroneous example removed. We thank Massimo Bianchi and Cumrun Vafa for pointing out this erro

    Book review: Oloketa tingting fo apem education long Solomon Islands: Issues in Solomon Islands Education.

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    Book review: Oloketa tingting fo apem education long Solomon Islands: Issues in Solomon Islands Education

    The Virtual Health Sciences Library of the Balearic Islands: A regional project for libraries cooperation.

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    Virtual Health Sciences Library of the Balearic Islands (Bibliosalut) is a regional project carried out in collaboration with the Regional Ministry of Health and Consumer Protection and the Health Service of the Balearic Islands (Ib-salut), through the Balearic Islands Biomedical Documentation Service. The Virtual Library Mission is to facilitate the most important scientific information to the public health professionals of the Balearic Islands, by using the new information and communication technologies, in order to contribute to the improvement of medical care quality, teaching, research and health managemen

    Electronic and magnetic influences of a stacking fault in cobalt nanoscale islands on the Ag(111) surface

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    Utilizing spin-polarized scanning tunneling microscopy and spectroscopy, we found coexistence of perpendicularly and in-plane magnetized cobalt nanoscale islands on the Ag(111) surface, and the relationship between the moire corrugation amplitude and the magnetization direction of the islands; the islands with the stronger moire corrugation show the perpendicular magnetization, and the ones with the weaker moire corrugation do the in-plane. Density functional theory calculations reproduce the relationship and explain the differences between the two types of the islands with an fcc stacking fault in the intrinsic hcp stacking of cobalt.Comment: 8 pages, 8 figure
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