197 research outputs found

    Phonological facilitation of grammatical gender retrieval.

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    In Dutch, the gender of nouns is marked by the definite articles de (common gender) and het (neuter gender). Most models of language production assume that gender information is retrieved via the noun's syntactic representation (or lemma). The authors test Caramazza's (1997) alternative proposal, according to which gender information is retrieved via the noun's phonological word form (or lexeme). In three picture-word experiments, which differed in the tasks to be performed (noun production, article+noun production, article production, and gender decision), clear phonological effects were obtained in tasks involving the retrieval of the noun's gender information. It is argued that traditional models of language production have difficulty in accounting for the occurrence and/or the size of these effects whereas they follow quite naturally from Caramazza's (1997) Independent Network model. © 2004 Psychology Press Ltd

    Portuguese category norms for children

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    This study presents Portuguese category norms for children of three different age groups: preschoolers (3- to 4-year-olds), second graders (7- to 8-year-olds), and preadolescents (11- to 12-year-olds). Three hundred Portuguese children (100 in each group) completed an exemplar-generation task. Preschoolers generated exemplars for 13 categories, second graders generated exemplars for 17 categories, and preadolescents generated exemplars for 21 categories. For each group, responses within each category were organized according to frequency of production in order to derive exemplar-production norms for sets of tested categories. The results also included information about the number of responses and exemplars, idiosyncratic and inappropriate responses, and commonality and diversity indexes for all the categories. A comparison of these children’s norms with the Portuguese adult norms was also presented. The full set of norms may be downloaded from www.psychonomic.org/archive

    The elusive archaeology of Kongo urbanism: the case of Kindoki, Mbanza Nsundi (Lower Congo, DRC)

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    We present here results, analyses and an in-depth historical contextualisation of the fieldwork undertaken in 2012 and 2013 at the Kindoki site in the Lower Congo (DRC). This site is linked with Mbanza Nsundi, one of the Kongo Kingdom's provincial capitals, which turns out to be archaeologically 'elusive'. Pinpointing its location proved to be particularly challenging. To this end, a historically-informed excavation methodology was developed that was never implemented in Central Africa before. We combined a strategy of systematic test pits with a large-scale 50 m grid approach. A cemetery was identified on Kindoki Hill with distinct but contemporaneous quarters of a 16th-17thcenturies settlement on both sides. The cemetery itself contains mainly 18th-century burials, in all likelihood of successive Nsundi rulers. The foreign, especially Portuguese, ceramics excavated on the hilltop and the hundreds of Venetian and likely Bavarian beads found in the graves are indicative of Mbanza Nsundi's connection to trade routes linking the Atlantic coast with the Pool region. The most striking discovery is that of a previously unknown type of comb-impressed pottery, from a pit with a calibrated radiocarbon date AD 1294-1393 (2 sigma). This suggests that a settlement had been developing at Kindoki since at least the 14th century, which allows us, for the very first time, to spatially bridge Kongo history and 'prehistory'. For the entire Lower Congo region only three 14C dates posterior to AD 1000 were available before the start of the KongoKing project, twelve have been added for just Kindoki

    Maroon Archaeology Beyond the Americas: A View From Kenya

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    Archaeological research on Maroons—that is, runaway slaves—has been largely confined to the Americas. This essay advocates a more global approach. It specifically uses two runaway slave communities in 19th-century coastal Kenya to rethink prominent interpretive themes in the field, including “Africanisms,” Maroons’ connections to indigenous groups, and Maroon group cohesion and identity. This article’s analysis demonstrates that the comparisons enabled by a more globalized perspective benefit the field. Instead of eliding historical and cultural context, these comparisons support the development of more localized and historically specific understandings of individual runaway slave communities both in Kenya and throughout the New World

    Search for subsolar-mass black hole binaries in the second part of Advanced LIGO’s and Advanced Virgo’s third observing run

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    We describe a search for gravitational waves from compact binaries with at least one component with mass 0.2–1.0 M and mass ratio q ≥ 0.1 in Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and Advanced Virgo data collected between 2019 November 1, 15:00 UTC and 2020 March 27, 17:00 UTC. No signals were detected. The most significant candidate has a false alarm rate of 0.2 yr−1. We estimate the sensitivity of our search over the entirety of Advanced LIGO’s and Advanced Virgo’s third observing run, and present the most stringent limits to date on the merger rate of binary black holes with at least one subsolar-mass component. We use the upper limits to constrain two fiducial scenarios that could produce subsolar-mass black holes: primordial black holes (PBH) and a model of dissipative dark matter. The PBH model uses recent prescriptions for the merger rate of PBH binaries that include a rate suppression factor to effectively account for PBH early binary disruptions. If the PBHs are monochromatically distributed, we can exclude a dark matter fraction in PBHs fPBH 0.6 (at 90 per cent confidence) in the probed subsolar-mass range. However, if we allow for broad PBH mass distributions, we are unable to rule out fPBH = 1. For the dissipative model, where the dark matter has chemistry that allows a small fraction to cool and collapse into black holes, we find an upper bound fDBH < 10−5 on the fraction of atomic dark matter collapsed into black holes

    Open Data from the Third Observing Run of LIGO, Virgo, KAGRA, and GEO

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    The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages

    Model-based cross-correlation search for gravitational waves from the low-mass X-ray binary Scorpius X-1 in LIGO O3 data

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    Search for subsolar-mass black hole binaries in the second part of Advanced LIGO's and Advanced Virgo's third observing run

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    We describe a search for gravitational waves from compact binaries with at least one component with mass 0.2 MM_\odot -- 1.0M1.0 M_\odot and mass ratio q0.1q \geq 0.1 in Advanced LIGO and Advanced Virgo data collected between 1 November 2019, 15:00 UTC and 27 March 2020, 17:00 UTC. No signals were detected. The most significant candidate has a false alarm rate of 0.2 yr1\mathrm{yr}^{-1}. We estimate the sensitivity of our search over the entirety of Advanced LIGO's and Advanced Virgo's third observing run, and present the most stringent limits to date on the merger rate of binary black holes with at least one subsolar-mass component. We use the upper limits to constrain two fiducial scenarios that could produce subsolar-mass black holes: primordial black holes (PBH) and a model of dissipative dark matter. The PBH model uses recent prescriptions for the merger rate of PBH binaries that include a rate suppression factor to effectively account for PBH early binary disruptions. If the PBHs are monochromatically distributed, we can exclude a dark matter fraction in PBHs fPBH0.6f_\mathrm{PBH} \gtrsim 0.6 (at 90% confidence) in the probed subsolar-mass range. However, if we allow for broad PBH mass distributions we are unable to rule out fPBH=1f_\mathrm{PBH} = 1. For the dissipative model, where the dark matter has chemistry that allows a small fraction to cool and collapse into black holes, we find an upper bound fDBH<105f_{\mathrm{DBH}} < 10^{-5} on the fraction of atomic dark matter collapsed into black holes.Comment: https://dcc.ligo.org/P220013

    Model-based cross-correlation search for gravitational waves from the low-mass X-ray binary Scorpius X-1 in LIGO O3 data

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    We present the results of a model-based search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1 using LIGO detector data from the third observing run of Advanced LIGO, Advanced Virgo and KAGRA. This is a semicoherent search which uses details of the signal model to coherently combine data separated by less than a specified coherence time, which can be adjusted to balance sensitivity with computing cost. The search covered a range of gravitational-wave frequencies from 25Hz to 1600Hz, as well as ranges in orbital speed, frequency and phase determined from observational constraints. No significant detection candidates were found, and upper limits were set as a function of frequency. The most stringent limits, between 100Hz and 200Hz, correspond to an amplitude h0 of about 1e-25 when marginalized isotropically over the unknown inclination angle of the neutron star's rotation axis, or less than 4e-26 assuming the optimal orientation. The sensitivity of this search is now probing amplitudes predicted by models of torque balance equilibrium. For the usual conservative model assuming accretion at the surface of the neutron star, our isotropically-marginalized upper limits are close to the predicted amplitude from about 70Hz to 100Hz; the limits assuming the neutron star spin is aligned with the most likely orbital angular momentum are below the conservative torque balance predictions from 40Hz to 200Hz. Assuming a broader range of accretion models, our direct limits on gravitational-wave amplitude delve into the relevant parameter space over a wide range of frequencies, to 500Hz or more

    Open data from the third observing run of LIGO, Virgo, KAGRA and GEO

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    The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in April of 2019 and lasting six months, O3b starting in November of 2019 and lasting five months, and O3GK starting in April of 2020 and lasting 2 weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main dataset, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages.Comment: 27 pages, 3 figure
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