Correlação entre fatores de experiência linguística bilíngue e controle inibitório

Não há ainda uma resposta definitiva para o debate quanto à existência da vantagem cognitiva bilíngue nas funções do controle executivo proposta por parte da literatura (BIALYSTOK; BARAC, 2013). Uma revisão bibliográfica pós-2011 (PAAP; JOHNSON; SAWI, 2015) identificou que a maioria das pesquisas que buscam por uma vantagem bilíngue nas funções executivas retorna resultados nulos e que, portanto, tal vantagem não existiria ou apareceria somente em circunstâncias específicas que ainda não foram determinadas. A presente pesquisa exploratória teve por objetivo investigar alguns fatores que podem contribuir para a caracterização dessas circunstâncias específicas. Mais especificamente, este estudo correlacionou fatores de experiência linguística bilíngue com o controle inibitório, uma das três grandes subdivisões das funções executivas (MIYAKE; FRIEDMAN, 2012), medido através do efeito Simon. Descobriu-se que o efeito Simon (medido em tempo de reação), ao contrário do que indicaria a lógica encontrada na literatura da área, se correlacionou positivamente com a quantidade de mixing (mistura de duas ou mais línguas ao se comunicar) que os bilíngues efetuavam. Houve também correlação negativa entre o tempo de reação no efeito Simon e a idade de aquisição média de uma L3. Dessa forma, quanto mais mixing os bilíngues efetuaram e quanto mais cedo eles começaram a utilizar uma L3, menor a sua capacidade de controle inibitório (maior efeito Simon). Tais evidências vão em encontro às concepções acerca da relação entre fatores de experiência linguística e funções executivas. No entanto, são contrárias à literatura anterior, que preveria que o mixing estaria associado a um efeito Simon menor.There is yet no definite answer to the debate regarding the existence of a bilingual cognitive advantage in the executive control functions as proposed by part of the literature (BIALYSTOK; BARAC, 2013). A post-2011 review (PAAP; JOHNSON; SAWI, 2015) found that most studies looking for a bilingual advantage in the executive functions yield null results and that, therefore, such advantage may not exist or may appear in specific circumstances that have yet to be determined. This exploratory research aims to investigate some factors that can contribute to the characterization of these specific circumstances. More specifically, the study correlated bilingual linguistic experience factors to inhibitory control, one of the three main subdivisions of the executive functions (MIYAKE; FRIEDMAN, 2012), as measured by the Simon effect. It was found that the Simon effect (measured in response time), differently from what would be expected from reading the literature, correlated negatively to the amount of mixing (of two or more languages while speaking) the bilinguals performed. There was also a negative correlation between response time in the Simon effect and the age of acquisition of a third language. This means that the more mixing the bilinguals performed and the earlier they started using a third language, the lower their inhibitory control ability (bigger Simon effect) was. Such evidences follow the conceptions about the relationship between linguistic experience and executive functions. However, they go in the opposite direction than the one proposed by the previous literature, which would predict mixing to be associated with a smaller Simon effect

Correlation between bilingual linguistic experience factors and inhibitory control

Há um debate na literatura quanto à existência da vantagem bilíngue nas funções executivas e fatores linguísticos possivelmente associados a ela. Esta pesquisa exploratória teve por objetivo investigar quais fatores de experiência linguística bilíngue podem estar correlacionados com a vantagem bilíngue no controle inibitório. Descobriu-se que o controle inibitório se correlacionou positivamente com a quantidade de mixing (mistura de duas ou mais línguas ao se comunicar) que os bilíngues efetuavam. Houve também correlação negativa entre o controle inibitório e a idade de aquisição média de uma L3. Ambas as evidências estão em desacordo com as concepções acerca da relação entre fatores de experiência linguística e funções executivas vigentes na literatura, que preveria que a realização de mixing e a idade de aquisição de uma L3 estariam associados a um controle inibitório maior.There is an ongoing debate in the literature on the hypothesis of a bilingual advantage in the executive functions and linguistic factors possibly related to it. This exploratory research aimed to investigate which bilingual linguistic experience factors could be correlated to inhibitory control. It was found that the inhibitory control correlated negatively to the amount of mixing (of two or more languages while speaking) the bilinguals performed. There was also a negative correlation between inhibitory control and the mean age of acquisition of a third language. The evidence goes against the conceptions on the relationship between linguistic experience factors and executive functions found in the literature, which would predict that the amount of mixing and age of acquisition of a third language would be associated with higher inhibitory control

Correlação entre fatores de experiência linguística bilíngue e controle inibitório = Correlation between bilingual linguistic experience factors and inhibitory control

Há um debate na literatura quanto à existência da vantagem bilíngue nas funções executivas e fatores linguísticos possivelmente associados a ela. Esta pesquisa exploratória teve por objetivo investigar quais fatores de experiência linguística bilíngue podem estar correlacionados com a vantagem bilíngue no controle inibitório. Descobriu-se que o controle inibitório se correlacionou positivamente com a quantidade de mixing (mistura de duas ou mais línguas ao se comunicar) que os bilíngues efetuavam. Houve também correlação negativa entre o controle inibitório e a idade de aquisição média de uma L3. Ambas as evidências estão em desacordo com as concepções acerca da relação entre fatores de experiência linguística e funções executivas vigentes na literatura, que preveria que a realização de mixing e a idade de aquisição de uma L3 estariam associados a um controle inibitório maio

The masses of Local Group dwarf spheroidal galaxies: The death of the universal mass profile

We investigate the claim that all dwarf spheroidal galaxies (dSphs) reside within halos that share a common, universal mass profile as has been derived for dSphs of the Galaxy. By folding in kinematic information for 25 Andromeda dSphs, more than doubling the previous sample size, we find that a singular mass profile can not be found to fit all the observations well. Further, the best-fit dark matter density profile measured for solely the Milky Way dSphs is marginally discrepant (at just beyond the 1 sigma level) with that of the Andromeda dSphs, where a profile with lower maximum circular velocity, and hence mass, is preferred. The agreement is significantly better when three extreme Andromeda outliers, And XIX, XXI and XXV, all of which have large half-light radii (>600pc) and low velocity dispersions (sigma_v < 5km/s) are omitted from the sample. We argue that the unusual properties of these outliers are likely caused by tidal interactions with the host galaxy.Comment: ApJ in press, 16 pages, 7 figures. Updated to address referee comment

A kinematic study of the Andromeda dwarf spheroidal system

We present a homogeneous kinematic analysis of red giant branch stars within 18 of the 28 Andromeda dwarf spheroidal (dSph) galaxies, obtained using the Keck I LRIS and Keck II DEIMOS spectrographs. Based on their g-i colors (taken with the CFHT MegaCam imager), physical positions on the sky, and radial velocities, we assign probabilities of dSph membership to each observed star. Using this information, the velocity dispersions, central masses and central densities of the dark matter halos are calculated for these objects, and compared with the properties of the Milky Way dSph population. We also measure the average metallicity ([Fe/H]) from the co-added spectra of member stars for each M31 dSph and find that they are consistent with the trend of decreasing [Fe/H] with luminosity observed in the Milky Way population. We find that three of our studied M31 dSphs appear as significant outliers in terms of their central velocity dispersion, And XIX, XXI and XXV, all of which have large half-light radii (>700 pc) and low velocity dispersions (sigma_v<5 km/s). In addition, And XXV has a mass-to-light ratio within its half-light radius of just [M/L]_{half}=10.3^{+7.0}_{-6.7}, making it consistent with a simple stellar system with no appreciable dark matter component within its 1 sigma uncertainties. We suggest that the structure of the dark matter halos of these outliers have been significantly altered by tides.Comment: 41 pages, 23 figures. Accepted for publication in Ap

A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy

Dwarf satellite galaxies are thought to be the remnants of the population of primordial structures that coalesced to form giant galaxies like the Milky Way. An early analysis noted that dwarf galaxies may not be isotropically distributed around our Galaxy, as several are correlated with streams of HI emission, and possibly form co-planar groups. These suspicions are supported by recent analyses, and it has been claimed that the apparently planar distribution of satellites is not predicted within standard cosmology, and cannot simply represent a memory of past coherent accretion. However, other studies dispute this conclusion. Here we report the existence (99.998% significance) of a planar sub-group of satellites in the Andromeda galaxy, comprising approximately 50% of the population. The structure is vast: at least 400 kpc in diameter, but also extremely thin, with a perpendicular scatter <14.1 kpc (99% confidence). Radial velocity measurements reveal that the satellites in this structure have the same sense of rotation about their host. This finding shows conclusively that substantial numbers of dwarf satellite galaxies share the same dynamical orbital properties and direction of angular momentum, a new insight for our understanding of the origin of these most dark matter dominated of galaxies. Intriguingly, the plane we identify is approximately aligned with the pole of the Milky Way's disk and is co-planar with the Milky Way to Andromeda position vector. The existence of such extensive coherent kinematic structures within the halos of massive galaxies is a fact that must be explained within the framework of galaxy formation and cosmology.Comment: Published in the 3rd Jan 2013 issue of Nature. 19 pages, 4 figures, 1 three-dimensional interactive figure. To view and manipulate the 3-D figure, an Adobe Reader browser plug-in is required; alternatively save to disk and view with Adobe Reade

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

The large-scale structure of the halo of the Andromeda galaxy II. Hierarchical structure in the Pan-Andromeda Archaeological Survey

The Pan-Andromeda Archaeological Survey is a survey of $>400$ square degrees centered on the Andromeda (M31) and Triangulum (M33) galaxies that has provided the most extensive panorama of a $L_\star$ galaxy group to large projected galactocentric radii. Here, we collate and summarise the current status of our knowledge of the substructures in the stellar halo of M31, and discuss connections between these features. We estimate that the 13 most distinctive substructures were produced by at least 5 different accretion events, all in the last 3 or 4 Gyrs. We suggest that a few of the substructures furthest from M31 may be shells from a single accretion event. We calculate the luminosities of some prominent substructures for which previous estimates were not available, and we estimate the stellar mass budget of the outer halo of M31. We revisit the problem of quantifying the properties of a highly structured dataset; specifically, we use the OPTICS clustering algorithm to quantify the hierarchical structure of M31's stellar halo, and identify three new faint structures. M31's halo, in projection, appears to be dominated by two `mega-structures', that can be considered as the two most significant branches of a merger tree produced by breaking M31's stellar halo into smaller and smaller structures based on the stellar spatial clustering. We conclude that OPTICS is a powerful algorithm that could be used in any astronomical application involving the hierarchical clustering of points. The publication of this article coincides with the public release of all PAndAS data products.Comment: Accepted for publication in the Astrophysical Journal. 51 pages, 24 figures, 5 tables. Some figures have degraded resolution. All PAndAS data products are available via the CADC at http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/community/pandas/query.html where you can also find a version of the paper with full resolution figure

First Sagittarius A* Event Horizon Telescope results. II. EHT and multiwavelength observations, data processing, and calibration

We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during the 2017 April 5–11 campaign. The observations were carried out with eight facilities at six locations across the globe. Novel calibration methods are employed to account for Sgr A*'s flux variability. The majority of the 1.3 mm emission arises from horizon scales, where intrinsic structural source variability is detected on timescales of minutes to hours. The effects of interstellar scattering on the image and its variability are found to be subdominant to intrinsic source structure. The calibrated visibility amplitudes, particularly the locations of the visibility minima, are broadly consistent with a blurred ring with a diameter of ∼50 μas, as determined in later works in this series. Contemporaneous multiwavelength monitoring of Sgr A* was performed at 22, 43, and 86 GHz and at near-infrared and X-ray wavelengths. Several X-ray flares from Sgr A* are detected by Chandra, one at low significance jointly with Swift on 2017 April 7 and the other at higher significance jointly with NuSTAR on 2017 April 11. The brighter April 11 flare is not observed simultaneously by the EHT but is followed by a significant increase in millimeter flux variability immediately after the X-ray outburst, indicating a likely connection in the emission physics near the event horizon. We compare Sgr A*'s broadband flux during the EHT campaign to its historical spectral energy distribution and find that both the quiescent emission and flare emission are consistent with its long-term behavior.http://iopscience.iop.org/2041-8205Physic

First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multiwavelength Observations, Data Processing, and Calibration

We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during the 2017 April 5–11 campaign. The observations were carried out with eight facilities at six locations across the globe. Novel calibration methods are employed to account for Sgr A*'s flux variability. The majority of the 1.3 mm emission arises from horizon scales, where intrinsic structural source variability is detected on timescales of minutes to hours. The effects of interstellar scattering on the image and its variability are found to be subdominant to intrinsic source structure. The calibrated visibility amplitudes, particularly the locations of the visibility minima, are broadly consistent with a blurred ring with a diameter of ∼50 μas, as determined in later works in this series. Contemporaneous multiwavelength monitoring of Sgr A* was performed at 22, 43, and 86 GHz and at near-infrared and X-ray wavelengths. Several X-ray flares from Sgr A* are detected by Chandra, one at low significance jointly with Swift on 2017 April 7 and the other at higher significance jointly with NuSTAR on 2017 April 11. The brighter April 11 flare is not observed simultaneously by the EHT but is followed by a significant increase in millimeter flux variability immediately after the X-ray outburst, indicating a likely connection in the emission physics near the event horizon. We compare Sgr A*’s broadband flux during the EHT campaign to its historical spectral energy distribution and find that both the quiescent emission and flare emission are consistent with its long-term behavior