Executive functioning and prospective memory in young children

The current study examined the role of executive functioning (EF) in children's prospective memory (PM) by assessing the effect of delay and number of intentions to-be-remembered on PM, as well as relations between PM and EF. Ninety-six 4-, 5-, and 6-year-olds completed a PM task and two executive function tasks. The PM task required children to interrupt an ongoing card game to perform one action (single intention) or two actions (dual intention) with target cards after a short delay (1 min) or a long delay (5 min). There was no main effect of number of intentions or delay on the PM task. However, performance improved with age, and age and delay interacted such that 4-year-olds’ performance remained the same after a long delay whereas 5-year-olds’ performance improved after a long delay. We suggest that the age by delay interaction is a product of age differences in cognitive monitoring. Working memory but not inhibitory control predicted PM with age controlled. We argue that an executive function framework permits an integrative understanding of many processes involved in young children's prospective memory

The role of subvocal rehearsal in preschool children’s prospective memory

4-year-olds had worse PM than 5-year-olds.•Children in the verbal interference condition had worse PM compared to children in the standard condition.•PM performance was correlated with verbal working memory and receptive vocabulary in the verbal interference condition only.•Children with better verbal ability were better able to cope with verbal interference to the benefit of their PM performance. The current study examined the impact of a verbal interference manipulation on 4- and 5- year olds’ prospective memory (PM). Children were randomly assigned to either complete a quiet delay activity (standard condition) or answer questions aloud during the delay activity (verbal interference condition). Children then completed a PM task followed by several individual differences measures (verbal working memory, inhibitory control, and receptive vocabulary). Four-year-olds showed worse PM than 5-year-olds, children in the verbal interference condition showed worse PM compared to the standard condition, and there was a marginal interaction between age and condition driven by poor performance of 4-year-olds in the verbal interference condition. PM performance was positively correlated with verbal working memory and receptive vocabulary (but not inhibitory control) in the verbal interference condition only suggesting that children with better verbal abilities were more able to cope with verbal interference to the benefit of their PM

A framework to identify constraints to post-extinction recovery of plant species—Application to the case of Bromus bromoideus

The reintroduction of plant species is a technique increasingly used to restore extirpated populations. Although most often used to improve the conservation status of endangered species, it can also be considered for species extinct in the wild. The process of resurrecting extinct plant species is however still in its infancy, and it entails additional challenges compared to the reintroduction of locally extinct populations. This study proposes a framework to analyse constraints to post-extinction recovery based on the case of Bromus bromoideus, a species endemic to southern Belgium and northern France, extinct in the wild since 1935. The plant still exists in ex situ collections, and seeds stored for decades at 5% moisture content and -20 °C have shown a good viability. We initiated a feasibility study to assess the risks associated to a programme aiming at reviving this long-extinct species. Several constraints were identified. Biological constraints are related to the fuzzy taxonomy of the species, the unknown origin of the seeds and undocumented ex situ cultivation, and the likely low genetic diversity of the material available for reintroduction. Ecological constraints are linked to the habitat of the species. B. bromoideus has no known natural habitat and is only found in cultivated fields, which are by definition highly anthropized unprotected areas. This study shows the importance of undertaking a preliminary study that addresses all aspects of technical feasibility, scientific justification, biological and societal risks. Based on this exercise and inspired by international standards, we developed a decision tool to assist conservationists to resurrect a plant species in the best possible way

The roles of perspective and language in children’s ability to delay gratification

We manipulated psychological distance in a delay of gratification paradigm. Younger children showed an other-over-self advantage but older children did not. Using “want” vs. “should” did not impact children’s delay of gratification. Increasing psychological distance is an established method for improving children’s performance in a number of self-regulation tasks. For example, using a delay of gratification (DoG) task, Prencipe and Zelazo (Psychological Science, 2005, Vol. 16, pp. 501–505) showed that 3-year-olds delay more for “other” than they do for “self,” whereas 4-year-olds make similar choices for self and other. However, to our knowledge, no work has manipulated language to increase psychological distance in children. In two experiments, we sought to manipulate psychological distance by replicating Prencipe and Zelazo’s age-related findings and extending them to older children (Experiment 1) and also sought to manipulate psychological distance using the auxiliary verbs “want” and “should” to prime more impulsive preference-based decisions or more normative optimal decisions (Experiment 2). In Experiment 1, 96 3- to 7-year-olds showed age-related improvements and interactive effects between age and perspective on DoG performance. In Experiment 2, 132 3- to 7-year-olds showed age-related improvements and a marginal interaction between age and perspective on DoG performance, but no effect of auxiliary verbs was detected. Results are discussed in terms of differing developmental trajectories of DoG for self and other due to psychological distancing, and how taking another’s perspective may boost DoG in younger children but not older children

X-Shooting ULLYSES: Massive stars at low metallicity. III. Terminal wind speeds of ULLYSES massive stars

The winds of massive stars have an impact on stellar evolution and on the surrounding medium. The maximum speed reached by these outflows, the terminal wind speed, is a global wind parameter and an essential input for models of stellar atmospheres and feedback. With the arrival of the ULLYSES programme, a legacy UV spectroscopic survey with HST, we have the opportunity to quantify the wind speeds of massive stars at sub-solar metallicity (in the Large and Small Magellanic Clouds, 0.5Z and 0.2Z) at an unprecedented scale. We empirically quantify the wind speeds of a large sample of OB stars, including supergiants, giants, and dwarfs at sub-solar metallicity. Using these measurements, we investigate trends of terminal wind speed with a number of fundamental stellar parameters, namely effective temperature, metallicity, and surface escape velocity. We empirically determined the terminal wind speed for a sample of 149 OB stars in the Magellanic Clouds either by directly measuring the maximum velocity shift of the absorption component of the Civ 1548-1550 line profile, or by fitting synthetic spectra produced using the Sobolev with exact integration method. Stellar parameters were either collected from the literature, obtained using spectral-type calibrations, or predicted from evolutionary models. We find strong trends of terminal wind speed with effective temperature and surface escape speed when the wind is strong enough to cause a saturated P Cygni profile in Civ 1548-1550. We find evidence for a metallicity dependence on the terminal wind speed proportional to Z^0.22+-0.03 when we compared our results to previous Galactic studies. Our results suggest that effective temperature rather than surface escape speed should be used as a straightforward empirical prediction of terminal wind speed and that the observed metallicity dependence is steeper than suggested by earlier works.Comment: 21 pages, 16 figures, 8 tables. Accepted in A&

X-Shooting ULLYSES: Massive stars at low metallicity: I. Project description

Observations of individual massive stars, super-luminous supernovae, gamma-ray bursts, and gravitational wave events involving spectacular black hole mergers indicate that the low-metallicity Universe is fundamentally different from our own Galaxy. Many transient phenomena will remain enigmatic until we achieve a firm understanding of the physics and evolution of massive stars at low metallicity (Z). The Hubble Space Telescope has devoted 500 orbits to observing ∼250 massive stars at low Z in the ultraviolet (UV) with the COS and STIS spectrographs under the ULLYSES programme. The complementary X-Shooting ULLYSES (XShootU) project provides an enhanced legacy value with high-quality optical and near-infrared spectra obtained with the wide-wavelength coverage X-shooter spectrograph at ESOa's Very Large Telescope. We present an overview of the XShootU project, showing that combining ULLYSES UV and XShootU optical spectra is critical for the uniform determination of stellar parameters such as effective temperature, surface gravity, luminosity, and abundances, as well as wind properties such as mass-loss rates as a function of Z. As uncertainties in stellar and wind parameters percolate into many adjacent areas of astrophysics, the data and modelling of the XShootU project is expected to be a game changer for our physical understanding of massive stars at low Z. To be able to confidently interpret James Webb Space Telescope spectra of the first stellar generations, the individual spectra of low-Z stars need to be understood, which is exactly where XShootU can deliver

X-shooting ULLYSES: massive stars at low metallicity

Context. The winds of massive stars have a significant impact on stellar evolution and on the surrounding medium. The maximum speed reached by these outflows, the terminal wind speed v∞, is a global wind parameter and an essential input for models of stellar atmospheres and feedback. With the arrival of the ULLYSES programme, a legacy UV spectroscopic survey with the Hubble Space Telescope, we have the opportunity to quantify the wind speeds of massive stars at sub-solar metallicity (in the Large and Small Magellanic Clouds, 0.5 Z⊙ and 0.2 Z⊙, respectively) at an unprecedented scale. Aims. We empirically quantify the wind speeds of a large sample of OB stars, including supergiants, giants, and dwarfs at sub-solar metallicity. Using these measurements, we investigate trends of v∞ with a number of fundamental stellar parameters, namely effective temperature (Teff), metallicity (Z), and surface escape velocity vesc. Methods. We empirically determined v∞ for a sample of 149 OB stars in the Magellanic Clouds either by directly measuring the maximum velocity shift of the absorption component of the C IV λλ1548–1550 line profile, or by fitting synthetic spectra produced using the Sobolev with exact integration method. Stellar parameters were either collected from the literature, obtained using spectral-type calibrations, or predicted from evolutionary models. Results. We find strong trends of v∞ with Teff and vesc when the wind is strong enough to cause a saturated P Cygni profile in C IV λλ1548–1550. We find evidence for a metallicity dependence on the terminal wind speed v∞ ∝ Z0.22±0.03 when we compared our results to previous Galactic studies. Conclusions. Our results suggest that Teff rather than vesc should be used as a straightforward empirical prediction of v∞ and that the observed Z dependence is steeper than suggested by earlier works

The Tarantula Massive Binary Monitoring. V. R144: a wind-eclipsing binary with a total mass ≳140 <i>M</i>_⊙

Context. The evolution of the most massive stars and their upper-mass limit remain insufficiently constrained. Very massive stars are characterized by powerful winds and spectroscopically appear as hydrogen-rich Wolf-Rayet (WR) stars on the main sequence. R 144 is the visually brightest WR star in the Large Magellanic Cloud. R 144 was reported to be a binary, making it potentially the most massive binary observed yet. However, the orbit and properties of R 144 have yet to be established. Aims. Our aim is to derive the physical, atmospheric, and orbital parameters of R 144 and to interpret its evolutionary status. Methods. We performed a comprehensive spectral, photometric, orbital, and polarimetric analysis of R 144. We measured radial velocities via cross-correlation. Spectral disentangling was performed using the shift-and-add technique. We used the Potsdam Wolf-Rayet code for the spectral analysis. We further present X-ray and optical light curves of R 144, and we analyse the latter using a hybrid model combining wind eclipses and colliding winds to constrain the orbital inclination i. Results. R 144 is an eccentric (e = 0.51) 74.2-d binary comprising two relatively evolved (age ≈2 Myr), H-rich WR stars (surface mass fraction XH ≈ 0.4). The hotter primary (WN5/6h, T∗ = 50 kK) and the cooler secondary (WN6/7h, T∗ = 45 kK) have nearly equal masses of M sin3 i = 48.3 ± 1.8 M⊙ and 45.5 ± 1.9 M⊙, respectively. The combination of low rotation and H depletion observed in the system is reproduced well by contemporary evolution models that include boosted mass loss at the upper-mass end. The systemic velocity of R 144 and its relative isolation suggest that this binary was ejected as a runaway from the neighbouring R 136 cluster. The optical light curve shows a clear orbital modulation that can be explained as a combination of two processes: excess emission stemming from wind-wind collisions and double wind eclipses. Our light-curve model implies an orbital inclination of i = 60.4 ± 1.5°, resulting in accurately constrained dynamical masses of M1,dyn = 74 ± 4 M⊙ and M2,dyn = 69 ± 4 M⊙. Assuming that both binary components are core H-burning, these masses are difficult to reconcile with the derived luminosities (log L1,2 L⊙ = 6.44, 6.39), which correspond to evolutionary masses of the order of M1, ev ≈ 110 M⊙ and M2, ev ≈ 100 M⊙. Taken at face value, our results imply that both stars have high classical Eddington factors of Γe = 0.78 ± 0.10. If the stars are on the main sequence, their derived radii (R∗ ≈ 25 R⊙) suggest that they are only slightly inflated, even at this high Eddington factor. Alternatively, the stars could be core He-burning, strongly inflated from the regular size of classical WR stars (≈ 1 R⊙); this scenario could help resolve the observed mass discrepancy. Conclusions. R144 is one of the few very massive extragalactic binaries ever weighed without the usage of evolution models, but poses several challenges in terms of the measured masses of its components. To advance, we strongly advocate for future polarimetric, photometric, and spectroscopic monitoring of R 144 and other very massive binaries

IBD risk loci are enriched in multigenic regulatory modules encompassing putative causative genes.

GWAS have identified >200 risk loci for Inflammatory Bowel Disease (IBD). The majority of disease associations are known to be driven by regulatory variants. To identify the putative causative genes that are perturbed by these variants, we generate a large transcriptome data set (nine disease-relevant cell types) and identify 23,650 cis-eQTL. We show that these are determined by ∼9720 regulatory modules, of which ∼3000 operate in multiple tissues and ∼970 on multiple genes. We identify regulatory modules that drive the disease association for 63 of the 200 risk loci, and show that these are enriched in multigenic modules. Based on these analyses, we resequence 45 of the corresponding 100 candidate genes in 6600 Crohn disease (CD) cases and 5500 controls, and show with burden tests that they include likely causative genes. Our analyses indicate that ≥10-fold larger sample sizes will be required to demonstrate the causality of individual genes using this approach