624 research outputs found

    Determination of intercontinental baselines and Earth orientation using VLBI

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    A series of experiments was conducted during the last decade to explore the capability of very long baseline interferometry (VLBI) to measure the crustal and rotational motions of the Earth with accuracies at the centimeter level. The observing stations are those of NASA's Deep Space Network in California, Spain and Australia. A multiparameter fit to the observed values of delay and delay rate yields radio source positions, polar motion, universal time, the precession constant, baseline vectors, and solid Earth tides. Source positions are obtained with formal errors of the order of 0''.01. UT1-UTC and polar motion are determined at 49 epochs, with formal error estimates for the more recent data of 0.5 msec for UT1-UTC and 2 to 6 mas for polar motion. Intercontinental baseline lengths are determined with formal errors of 5 to 10 cm. The Love numbers and Earth tide phase lag agree with the commonly accepted values

    VLBI measurements of radio source positions at the Jet Propulsion Laboratory

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    The results of approximately 1300 observations of 67 radio sources are presented. Most of the measurements were made at the stations of the Deep Space Network in California, Spain, and Australia at wavelengths of 13.1 and 3.6 cm, between 1971 and 1978. The formal errors in the derived source positions are generally in the neighborhood of 0.01 seconds of arc and the positions agree fairly well with those previously published

    In need of mediation: The relation between syntax and information structure

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    This paper defends the view that syntax does not directly interact with information structure. Rather, information structure affects prosody, and only the latter has an interface with syntax. We illustrate this point by discussing scrambling, focus preposing, and topicalization. The position entertained here implies that syntax is not very informative when one wants to narrow down the interpretation of terms such as “focus”, “topic”, etc

    On the form-function dichotomy in linguistic theory

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    This paper focuses on an important divide in theoretical linguistics between two broad perspectives on the structural properties of human languages, generative and functionalist. In the former, linguistic structure is explained in terms of discrete categories and highly abstract principles, which may be language-independent or language-specific and purely formal or functional in nature. In the latter, explanation for why languages have the structure that they do is found ‘outside’ language, in the general principles of human cognition and the communicative functions of language. The aim of this paper is to highlight the need for abstractness, explicitness, simplicity and theoretical economy in linguistic description and explanation. The question is not whether principles of grammar are formal or functional. The question is whether the principles that are postulated to explain linguistic structure express true generalizations

    Temporally graded retrograde amnesia of contextual fear after hippocampal damage in rats: within-subjects examination

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    We have shown previously that electrolytic lesions of the dorsal hippocampus (DH) produce a severe deficit in contextual fear if made 1 d, but not 28 d, after fear conditioning (). As such, the hippocampus seems to play a time-limited role in the consolidation of contextual fear conditioning. Here, we examine retrograde amnesia of contextual fear produced by DH lesions in a within-subjects design. Unlike our previous reports, rats had both a remote and recent memory at the time of the lesion. Rats were given 10 tone-shock pairings in one context (remote memory) and 10 tone-shock pairings in a distinct context (with a different tone) 50 d later (recent memory), followed by DH or sham lesions 1 d later. Relative to controls, DH-lesioned rats exhibited no deficit in remote contextual fear, but recent contextual fear memory was severely impaired. They also did not exhibit deficits in tone freezing. This highly specific deficit in recent contextual memory demonstrated in a within-subjects design favors mnemonic over performance accounts of hippocampal involvement in fear. These findings also provide further support for a time-limited role of the hippocampus in memory storage.http://deepblue.lib.umich.edu/bitstream/2027.42/56234/1/anagJN99.pd

    The startled seahorse: is the hippocampus necessary for contextual fear conditioning?

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56233/2/davisTICS98.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/56233/1/marenTICS98.pd

    New vs. Given

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    This squib begins with an argument emphasizing that the grammar of English makes a distinction between constituents that are focused and those that are merely new, hence not given. If the distinction is made via features, we need two features: one indicating focus and one indicating either given or new information. Which one of the two? Semantically, the choice doesn’t matter: whatever information is given is not new and the other way round. For the phonology, there is a difference, however. If the prosody of all-new constituents is default prosody, but the prosody of given constituents is special, we would want to indicate givenness, rather than newness

    On the asymmetry of wh-doubling in varieties of German and Dutch

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    Theoretical and Experimental Linguistic
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