The emergence of large-scale replication projects yielding successful rates substantially lower than expected caused the behavioural, cognitive, and social sciences to experience a so-called ... Show moreThe emergence of large-scale replication projects yielding successful rates substantially lower than expected caused the behavioural, cognitive, and social sciences to experience a so-called ‘replication crisis’. In this Perspective, we reframe this ‘crisis’ through the lens of a credibility revolution, focusing on positive structural, procedural and community-driven changes. Second, we outline a path to expand ongoing advances and improvements. The credibility revolution has been an impetus to several substantive changes which will have a positive, long-term impact on our research environment. Show less
Gretzinger, J.; Sayer, D.; Justeau, P.; Altena, E.; Pala, M.; Dulias, K.; ... ; Schiffels, S. 2022
The history of the British Isles and Ireland is characterized by multiple periods of major cultural change, including the influential transformation after the end of Roman rule, which precipitated... Show moreThe history of the British Isles and Ireland is characterized by multiple periods of major cultural change, including the influential transformation after the end of Roman rule, which precipitated shifts in language, settlement patterns and material culture(1). The extent to which migration from continental Europe mediated these transitions is a matter of long-standing debate(2-4). Here we study genome-wide ancient DNA from 460 medieval northwestern Europeans-including 278 individuals from England-alongside archaeological data, to infer contemporary population dynamics. We identify a substantial increase of continental northern European ancestry in early medieval England, which is closely related to the early medieval and present-day inhabitants of Germany and Denmark, implying large-scale substantial migration across the North Sea into Britain during the Early Middle Ages. As a result, the individuals who we analysed from eastern England derived up to 76% of their ancestry from the continental North Sea zone, albeit with substantial regional variation and heterogeneity within sites. We show that women with immigrant ancestry were more often furnished with grave goods than women with local ancestry, whereas men with weapons were as likely not to be of immigrant ancestry. A comparison with present-day Britain indicates that subsequent demographic events reduced the fraction of continental northern European ancestry while introducing further ancestry components into the English gene pool, including substantial southwestern European ancestry most closely related to that seen in Iron Age France(5,6). Show less
We present an analysis of the spatial distribution of star formation in a sample of 60 visually identified galaxy merger candidates at z {\gt} 1. Our sample, drawn from the 3D-HST survey, is flux... Show moreWe present an analysis of the spatial distribution of star formation in a sample of 60 visually identified galaxy merger candidates at z {\gt} 1. Our sample, drawn from the 3D-HST survey, is flux limited and was selected to have high star formation rates based on fits of their broad-band, low spatial resolution spectral energy distributions. It includes plausible pre-merger (close pairs) and post-merger (single objects with tidal features) systems, with total stellar masses and star formation rates derived from multiwavelength photometry. Here we use near-infrared slitless spectra from 3D-HST which produce H{$α$} or [O III] emission line maps as proxies for star formation maps. This provides a first comprehensive high-resolution, empirical picture of where star formation occurred in galaxy mergers at the epoch of peak cosmic star formation rate. We find that detectable star formation can occur in one or both galaxy centres, or in tidal tails. The most common case (58 per cent) is that star formation is largely concentrated in a single, compact region, coincident with the centre of (one of) the merger components. No correlations between star formation morphology and redshift, total stellar mass or star formation rate are found. A restricted set of hydrodynamical merger simulations between similarly massive and gas-rich objects implies that star formation should be detectable in both merger components, when the gas fractions of the individual components are the same. This suggests that z {\tilde} 1.5 mergers typically occur between galaxies whose gas fractions, masses and/or star formation rates are distinctly different from one another. Show less
The assembly of galaxies can be described by the distribution of their star formation as a function of cosmic time. Thanks to the WFC3 grism on the Hubble Space Telescope (HST) it is now possible... Show moreThe assembly of galaxies can be described by the distribution of their star formation as a function of cosmic time. Thanks to the WFC3 grism on the Hubble Space Telescope (HST) it is now possible to measure this beyond the local Universe. Here we present the spatial distribution of H{$α$} emission for a sample of 54 strongly star-forming galaxies at z \~{} 1 in the 3D-HST Treasury survey. By stacking the H{$α$} emission, we find that star formation occurred in approximately exponential distributions at z \~{} 1, with a median Sérsic index of n = 1.0 {\plusmn} 0.2. The stacks are elongated with median axis ratios of b/a = 0.58 {\plusmn} 0.09 in H{$α$} consistent with (possibly thick) disks at random orientation angles. Keck spectra obtained for a subset of eight of the galaxies show clear evidence for rotation, with inclination corrected velocities of 90-330 km s$^{-1}$. The most straightforward interpretation of our results is that star formation in strongly star-forming galaxies at z \~{} 1 generally occurred in disks. The disks appear to be ''scaled-up'' versions of nearby spiral galaxies: they have EW(H{$α$}) \~{} 100 Å out to the solar orbit and they have star formation surface densities above the threshold for driving galactic scale winds. Show less
