717 research outputs found

    Re-assigning (1x2) reconstruction of rutile TiO_2(110) from DFT+U calculations

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    Physically reasonable electronic structures of reconstructed rutile TiO_2(110)-(1x2) surfaces were studied using density functional theory (DFT) supplemented with Hubbard U on-site Coulomb repulsion acting on the d electrons, so called as the DFT+U approach. Two leading reconstruction models proposed by Onishi--Iwasawa and Park et al. were compared in terms of their thermodynamic stabilities.Comment: 4 pages, 4 figures, 2 table

    Spectral formation in a radiative shock: application to anomalous X-ray pulsars and soft gamma-ray repeaters

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    In the fallback disk model for the persistent emission of Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs), the hard X-ray emission arises from bulk- and thermal Comptonization of bremsstrahlung photons, which are generated in the accretion column. The relatively low X-ray luminosity of these sources implies a moderate transverse optical depth to electron scattering, with photons executing a small number of shock crossings before escaping sideways. We explore the range of spectral shapes that can be obtained with this model and characterize the most important parameter dependencies. We use a Monte Carlo code to study the crisscrossing of photons in a radiative shock in an accretion column and compute the resulting spectrum. As expected, high-energy power-law X-ray spectra are produced in radiative shocks with photon-number spectral index larger than or about 0.5. We find that the required transverse optical depth is between 1 and 7. Such spectra are observed in low-luminosity X-ray pulsars. We demonstrate here with a simple model that Compton upscattering in the radiative shock in the accretion column can produce hard X-ray spectra similar to those seen in the persistent and transient emission of AXPs and SGRs. In particular, one can obtain a high-energy power-law spectrum, with photon-number spectral index ~ 1 and a cutoff at 100 - 200 keV, with a transverse Thomson optical depth of ~ 5, which is shown to be typical in AXPs/SGRs.Comment: Accepted for publication in A&

    Speaking and gesturing guide event perception during message conceptualization: Evidence from eye movements

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    Speakers’ visual attention to events is guided by linguistic conceptualization of information in spoken language production and in language-specific ways. Does production of language-specific co-speech gestures further guide speakers’ visual attention during message preparation? Here, we examine the link between visual attention and multimodal event descriptions in Turkish. Turkish is a verb-framed language where speakers’ speech and gesture show language specificity with path of motion mostly expressed within the main verb accompanied by path gestures. Turkish-speaking adults viewed motion events while their eye movements were recorded during non- linguistic (viewing-only) and linguistic (viewing-before-describing) tasks. The relative attention allocated to path over manner was higher in the linguistic task compared to the non-linguistic task. Furthermore, the relative attention allocated to path over manner within the linguistic task was higher when speakers (a) encoded path in the main verb versus outside the verb and (b) used additional path gestures accompanying speech versus not. Results strongly suggest that speakers’ visual attention is guided by language-specific event encoding not only in speech but also in gesture. This provides evidence consistent with models that propose integration of speech and gesture at the conceptualization level of language production and suggests that the links between the eye and the mouth may be extended to the eye and the hand

    Speaking but not gesturing predicts event memory: A cross-linguistic comparison

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    Every day people see, describe, and remember motion events. However, the relation between multimodal encoding of motion events in speech and gesture, and memory is not yet fully understood. Moreover, whether language typology modulates this relation remains to be tested. This study investigates whether the type of motion event information (path or manner) mentioned in speech and gesture predicts which information is remembered and whether this varies across speakers of typologically different languages. Dutch- and Turkish-speakers watched and described motion events and completed a surprise recognition memory task. For both Dutch- and Turkish-speakers, manner memory was at chance level. Participants who mentioned path in speech during encoding were more accurate at detecting changes to the path in the memory task. The relation between mentioning path in speech and path memory did not vary cross-linguistically. Finally, the co-speech gesture did not predict memory above mentioning path in speech. These findings suggest that how speakers describe a motion event in speech is more important than the typology of the speakers’ native language in predicting motion event memory. The motion event videos are available for download for future research at https://osf.io/p8cas/

    Monitoring sources of event memories: A cross-linguistic investigation

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    When monitoring the origins of their memories, people tend to mistakenly attribute mem- ories generated from internal processes (e.g., imagination, visualization) to perception. Here, we ask whether speaking a language that obligatorily encodes the source of informa- tion might help prevent such errors. We compare speakers of English to speakers of Turkish, a language that obligatorily encodes information source (direct/perceptual vs. indirect/hearsay or inference) for past events. In our experiments, participants reported having seen events that they had only inferred from post-event visual evidence. In general, error rates were higher when visual evidence that gave rise to inferences was relatively close to direct visual evidence. Furthermore, errors persisted even when participants were asked to report the specific sources of their memories. Crucially, these error patterns were equivalent across language groups, suggesting that speaking a language that obligatorily encodes source of information does not increase sensitivity to the distinction between per- ception and inference in event memory

    Late sign language exposure does not modulate the relation between spatial language and spatial memory in deaf children and adults

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    Prior work with hearing children acquiring a spoken language as their first language shows that spatial language and cognition are related systems and spatial language use predicts spatial memory. Here, we further investigate the extent of this relationship in signing deaf children and adults and ask if late sign language exposure, as well as the frequency and the type of spatial language use that might be affected by late exposure, modulate subsequent memory for spatial relations. To do so, we compared spatial language and memory of 8-year-old late-signing children (after 2 years of exposure to a sign language at the school for the deaf) and late-signing adults to their native-signing counterparts. We elicited picture descriptions of Left-Right relations in Turkish Sign Language (Türk İşaret Dili) and measured the subsequent recognition memory accuracy of the described pictures. Results showed that late-signing adults and children were similar to their native-signing counterparts in how often they encoded the spatial relation. However, late-signing adults but not children differed from their native-signing counterparts in the type of spatial language they used. However, neither late sign language exposure nor the frequency and type of spatial language use modulated spatial memory accuracy. Therefore, even though late language exposure seems to influence the type of spatial language use, this does not predict subsequent memory for spatial relations. We discuss the implications of these findings based on the theories concerning the correspondence between spatial language and cognition as related or rather independent systems

    Investigation of Heavy Metal Concentrations in The Gulf of Izmit (Marmara Sea) Altinova Shipyard Region

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    In this study, heavy metal concentrations (Ca, Mg, Hg, As, Sb, Ag, Al, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn, Ti, Th, U, Mo, Cd) amounts were measured by examining marine sediment samples obtained from the coasts of the Izmit Bay Altınova shipyards region. The natural and anthropogenic pollution levels of the region were revealed by the analysis of sediment samples. The extent to which the marine ecosystem may have been affected by the shipyard activities that have been actively carried out in the region for the last ten years was also investigated. Heavy metal analyses of sediment samples were carried out by the XRF method. In addition, the morphological and surface features of the sediment grains were obtained by SEM analysis, and the element contents of seawater samples obtained from the region were determined with an ICP-OES device. The heavy metal pollution level of the region was revealed by evaluation of the data obtained as a result of the analysis. The results of the XRF analysis showed that the heavy metals, which are toxic for humans, such as cadmium (max 17.984 ppm), lead (max 31.302 ppm), nickel (max 71.725 ppm) and arsenic (max 13.852 ppm) were detected. According to the results of elemental analysis with ICP-OES, Hg, As, Sb, Ag, Al, Co, Cr, Ni, Pb, V, Ti, U, Mo, and Cd were below the measurable limit. © 2022, Turkish Chemical Society. All rights reserved

    Clinical Results of 40 Consecutive Basal Thumb Prostheses and No CRPS Type I After Vitamin C Prophylaxis

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    Complex regional pain syndrome (CRPS) type I may occur as complication after any type of surgery for basal joint arthritis of the thumb. We investigated prospectively in an ongoing study our results after a fully standardized treatment with a total joint prosthesis under vitamin C prophylaxis
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