341 research outputs found

    An exemplar model should be able to explain all syntactic priming phenomena : a commentary on Ambridge (2020)

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    The authors argue that Ambridge’s radical exemplar account of language cannot clearly explain all syntactic priming evidence, such as inverse preference effects (greater priming for less frequent structures), and the contrast between short-lived lexical boost and long-lived abstract priming. Moreover, without recourse to a level of abstract syntactic structure, Ambridge’s account cannot explain abstract priming in amnesia patients or cross-linguistic priming. Instead, the authors argue that abstract representations remain the more parsimonious account for the wide variety of syntactic priming phenomena

    Aging and syntactic representations : evidence of preserved syntactic priming and lexical boost

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    Young adults can be primed to re-use a syntactic structure across otherwise unrelated utterances but it is not known whether this phenomenon exists in older adults. In a dialogue task, young and older adults described transitive verb target pictures after hearing active or passive sentences. Both groups were more likely to produce a passive sentence following a passive prime than following an active prime (indicating syntactic priming), and this effect increased when the prime and target involved the same verb (indicating lexical boost). These effects were statistically equivalent in young and older adults, suggesting that the syntactic representations underlying sentence production are unaffected by normal aging

    Age-related effects on lexical, but not syntactic, processes during sentence production

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    ABSTRACT We investigated the effect of healthy ageing on the lexical and syntactic processes involved in sentence production. Young and older adults completed a semantic interference sentence production task: we manipulated whether the target picture and distractor word were semantically related or unrelated and whether they fell within the same phrase (“the watch and the clock/hippo move apart”) or different phrases (“the watch moves above the clock/hippo”). Both age groups were slower to initiate sentences containing a larger, compared to a smaller, initial phrase, indicating a similar phrasal scope of advanced planning. However, older adults displayed significantly larger semantic interference effects (slower to initiate sentences when the target picture and distractor word were related) than young adults, indicating an age-related increase in lexical competition. Thus, while syntactic planning is preserved with age, older speakers encounter problems managing the temporal co-activation of competing lexical items during sentence production.publishedVersio

    Syntactic and lexical processing in healthy ageing

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    Successful sentence production requires rapid word retrieval and the generation of an appropriate grammatical structure. In this thesis, I investigated how these lexical and syntactic processes are affected by healthy ageing. In Chapter 2, using a structural priming paradigm, I found evidence that the nature of syntactic representations is unaffected by healthy ageing and that global, not internal, structure determined syntactic choices in young and older adults. In Chapters 3-4, using adaptations of the planning scope paradigm, I found that young and older adults engaged in a similar phrasal scope of advanced planning. However, I also found evidence of age-related differences in lexical processing in that older adults were less able to manage the temporal activation of lexical items and their integration into syntactic structures. In Chapter 5, I investigated sentence comprehension using the neuroimaging technique of MEG. In young adults, I found that the binding of words into a minimal sentence structure was associated with a modulation in alpha power. Overall, the findings of this thesis demonstrate that there is a complex relationship between healthy ageing and language, such that certain features of language may be preserved with age, while others decline

    The Holocene Geoarchaeology of the Desert Nile in Northern Sudan

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    Invited Paper Forty years ago Colin Renfrew declared that "every archaeological problem starts as a problem in geoarchaeology" (Renfrew, 1976 p. 2). With this assertion in mind, this paper draws upon the findings from field research in two sectors of the Nile Valley of Northern Sudan dedicated to the exploration of human-environment interactions during the middle and late Holocene. This part of the Nile corridor contains a rich cultural record and an exceptionally well preserved Holocene fluvial archive. A distinctive feature of these records is the variety of evidence for interaction between desert and river over a range of spatial and temporal scales. This interaction presented both challenges and opportunities for its ancient inhabitants. This paper will present evidence for large-scale landscape changes driven by shifts in global climate. It will also show how we have integrated the archaeological and geological records in the Northern Dongola Reach and at Amara West - where long-term field projects led by archaeologists from the British Museum have recognised the importance of a sustained commitment to interdisciplinary research to achieve a fully integrated geoarchaeological approach across a range of scales. The former project is a large-scale landscape survey with multiple sites across an 80 km reach of the Nile whilst the latter has a strong focus on a single New Kingdom town site and changes in its environmental setting. By combining multiple archaeological and geological datasets - and pioneering the use of OSL dating and strontium isotope analysis in the Desert Nile - we have developed a new understanding of human responses to Holocene climate and landscape change in this region. Renfrew, C. (1976) Archaeology and the earth sciences. In: D.A. Davidson and M.I. Shackley (eds) Geoarchaeology: Earth Science and the Past, Duckworth, London, 1-5

    Impact of drainage on soil-forming mechanisms in a French Albeluvisol: Input of mineralogical data in mass-balance modelling

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    International audienceResearch on soil pedogenesis has mainly focused on the long-term soil formation and has most often neglected recent soil evolutions in response to human practices. Such recent soil evolutions are however of considerable interest to study the timing of soil forming processes in response to changes in environmental conditions. In this paper, we model the Albeluvisol evolution in response to agricultural drainage. This was considered as a model case to study the velocity of mineralogical changes in soil as a result of eluviation and redox processes. We used a space-for-time substitution approach in combination with mass balance modelling based on mineralogical data in order to identify and characterise the mineralogical transformations responsible for the recent soil evolution in response to subsurface drainage. This approach allowed demonstrating that the main effects of subsurface drainage are (i) increasing precipitation of Mn oxides and Mn-rich ferrihydrite with decreasing distance to the drain as a result of the change in redox conditions and (ii) increasing loss of clay-sized oxides and smectites due to the enhanced eluviation in the vicinity of the drain. Both processes induce significant matter fluxes in comparison with those that occurred over the long-term soil formation. Nowadays, the precipitation of Mn oxides and Mn-rich ferrihydrite seems to still be active in the studied soil. On the opposite, the eluviation process appears less active than immediately after the drainage network installation, if not totally inactive. It thus demonstrates that some soil processes may have significant impact on the soil mineralogical composition even if they are only active over very short periods of time after a change in environmental conditions

    Trace element accumulation in Mn—Fe—oxide nodules of a planosolic horizon.

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    The aim of this work was to determine the importance of nodule formation on the dynamics of major and trace elements (TEs) along a Planosol toposequence developed in metamorphic parent material at La Châtre (Massif Central, France). The different horizons were sampled within three pits and analysed for major and trace element contents. The nodule-rich horizon was studied more closely. A simplified sequential extraction scheme, X-ray diffraction (XRD) and microscopic approaches were used in order to determine the individual phases containing TE in nodules. Along the slope, the nodule-rich horizon varies in thickness, is composed of different oxide fractions and has different scavenging efficiencies according to the TE considered. Iron was found to accumulate in the middle of the slope, while Mn accumulated at the base. The scavenging effect is only evident for Ni in profile 1. For Fe and Cu, it is maximal in profile 2 where the nodule-rich horizon is the thickest. For Pb and Mn, maximal scavenging effect is recorded for both profiles 2 and 3, in the lowest part of the slope. Cr is not accumulated at all. This was related to the water dynamic and the hydromorphic conditions prevailing along the slope. Results obtained by sequential extractions and associated X-ray diffraction on the different nodule size fractions and those obtained by electron microprobe allow inference of the TE distribution in nodules. Nodules were mainly composed of three to four types of cements surrounding grains of quartz, feldspars, micas and accessory minerals: iron-rich cements, Si- and Al-rich cements, Mn-rich cements and Ti-rich cements in places. The iron-rich cements consist of poorly crystalline goethite and possibly some ferrihydrite. Ferrihydrite is associated with Cr as demonstrated by extractions. Goethite contained Mn and most of the TE extracted except for Ni and Pb. Fine-grained Si- and Al-rich cements were also observed. They contain variable amounts of Ti and Mn. Mn-rich cements were not present in all the nodules and were mainly linked to the dark zones of the nodules. The nature of these Mn oxides could not be determined. They were found to contain Co, Ni, Cu and probably Pb

    Zinc Redistribution in a Soil Developed from Limestone During Pedogenesis

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    International audienceThe long-term redistribution of Zn in a naturally Zn-enriched soil during pedogenesis was quantified based on mass balance calculations. According to their fate, parent limestones comprised three Zn pools: bound to calcite and pyritesphalerite grains, bound to phyllosilicates and bound to goethite in the inherited phosphate nodules. Four pedological processes, i.e., carbonate dissolution, two stages of redox processes and eluviation, redistributed Zn during pedogenesis. The carbonate dissolution of limestones released Zn bound to calcite into soil solution. Due to residual enrichment, Zn concentrations in the soil are higher than those in parent limestones. Birnessite, ferrihydrite and goethite dispersed in soil horizon trapped high quantities of Zn during their formation. Afterwards, primary redox conditions induced the release of Zn and Fe into soil solution, and the subsequent individualization of Fe and Mn into Zn-rich concretions. Both processes and subsequent aging of the concretions formed induced significant exportation of Zn through the bottom water table. Secondary redox conditions promoted the weathering of Fe and Mn oxides in cements and concretions. This process caused other losses of Zn through lateral exportation in an upper water table. Concomitantly, eluviation occurred at the top of the solum. The lateral exportation of eluviated minerals through the upper water table limited illuviation. Eluviation was also responsible for Zn loss, but this Zn bound to phyllosilicates was not bioavailabl
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