The ‘Little Ice Age’ in the Southern Hemisphere in the context of the last 3000 years : Peat-based proxy-climate data from Tierra del Fuego

DM’s research (at Department of Earth Sciences, Uppsala University) was supported through a European Community Marie Curie Fellowship (Contract HPMF-CT-2000-01056).Peer reviewedPostprin

Plant–environment interactions from the lens of plant stress, reproduction, and mutualisms

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154416/1/ajb21437.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154416/2/ajb21437_am.pd

Into Africa : Molecular phylogenetics and historical biogeography of sub-Saharan African woodferns (Dryopteris)

PREMISE OF THE STUDY: Our goal was to infer the phylogenetic relationships and historical biogeography of the genus Dryopteris with a focus on taxa in sub-Saharan Africa and neighboring islands. In general, little is known about the relationships between African fern species and their congeners in other geographic regions, and our aim was to determine whether the sub-Saharan African species of Dryopteris are monophyletic and evolved within Africa or arrived there via repeated dispersals into Africa from other regions. METHODS: We obtained sequence data for five chloroplast markers from 214 species of Dryopteris and 18 outgroups. We performed phylogenetic and molecular dating analyses using a Bayesian relaxed clock method in BEAST with fossil and secondary calibration points and estimated ancestral ranges for the genus globally by comparing multiple models in BioGeoBEARS. KEY RESULTS: We found that 22 of 27 accessions of sub-Saharan African Dryopteris belong to a large clade of 31 accessions that also includes taxa from Indian and Atlantic Ocean islands. Additional accessions of taxa from our regions of interest have Asian, Hawaiian, European, or North American species as their closest relatives. CONCLUSIONS: The majority of sub-Saharan African Dryopteris species are descended from a shared common ancestor that dispersed to Africa from Asia approximately 10 Ma. There have been subsequent dispersal events from the African mainland to islands in the Atlantic and Indian Oceans, including Madagascar. Several additional species are estimated to have descended from ancestors that reached Africa via separate events over the last roughly 20 million years.Peer reviewe

Conserved thermal performance curves across the geographic range of a gametophytic fern.

Species-level responses to environmental change depend on the collective responses of their constituent populations and the degree to which populations are specialized to local conditions. Manipulative experiments in common-garden settings make it possible to test for population variation in species' responses to specific climate variables, including those projected to shift as the climate changes in the future. While this approach is being applied to a variety of plant taxa to evaluate their responses to climate change, these studies are heavily biased towards seed-bearing plant species. Given several unique morphological and physiological traits, fern species may exhibit very different responses from angiosperms and gymnosperms. Here, we tested the hypothesis that previously detected population differentiation in a fern species is due to differentiation in thermal performance curves among populations. We collected explants from six populations spanning the species' geographic range and exposed them to 10 temperature treatments. Explant survival, lifespan and the change in photosynthetic area were analysed as a function of temperature, source population and their interaction. Overall results indicated that explants performed better at the lowest temperature examined, and the threshold for explant performance reflects maximum temperatures likely to be experienced in the field. Surprisingly, explant fitness did not differ among source populations, suggesting that temperature is not the driver behind previously detected patterns of population differentiation. These results highlight the importance of other environmental axes in driving population differentiation across a species range, and suggest that the perennial life history strategy, asexual mating system and limited dispersal potential o

DARIAH Beyond Europe

International audienceDARIAH, the digital humanities infrastructure with origins and an organisational home in Europe, is nearing the completion of its implementation phase. The significant investment from the European Commission and member countries has yielded a robust set of technical and social infrastructures, ranging from working groups, various registries, pedagogical materials, and software to support diverse approaches to digital humanities scholarship. While the funding and leadership of DARIAH to date has come from countries in, or contiguous with, Europe, the needs that drive its technical and social development are widely shared within the international digital humanities community beyond Europe. Scholars on every continent would benefit from well-supported technical tools and platforms, directories for facilitating access to information and resources, and support for working groups.The DARIAH Beyond Europe workshop series, organised and financed under the umbrella of the DESIR project (“DARIAH ERIC Sustainability Refined,” 2017–2019, funded by the European Union’s Horizon 2020 Research and Innovation Program), convened three meetings between September 2018 and March 2019 in the United States and Australia. These workshops served as fora for cross-cultural exchange, and introduced many non-European DH scholars to DARIAH; each of the workshops included a significant delegation from various DARIAH bodies, together with a larger number of local presenters and participants. The local contexts for these workshops were significantly different in their embodiment of research infrastructures: on the one hand, in the U.S., a private research university (Stanford) and the de facto national library (the Library of Congress), both in a country with a history of unsuccessful national-scale infrastructure efforts; and in Australia, a system which has invested substantially more in coordinated national research infrastructure in science and technology, but very little on a national scale in the humanities and arts. Europe is in many respects ahead of both host countries in terms of its research infrastructure ecosystem both at the national and pan-European levels.The Stanford workshop had four main topics of focus: corpus management; text and image analysis; geohumanities; and music, theatre, and sound studies. As the first of the workshops, the Stanford group also took the lead in proposing next steps toward exploring actionable “DARIAH beyond Europe” initiatives, including the beginnings of a blog shared among participants from all the workshops, extra-European use of DARIAH’s DH Course Registry, and non-European participation in DARIAH Working Groups.The overall theme of the Library of Congress workshop was “Collections as Data,” building on a number of U.S.-based initiatives exploring how to enhance researcher engagement with digital collections through computationally-driven research. In Washington, D.C., the knowledge exchange sessions focussed on digitised newspapers and text analysis, infrastructural challenges for public humanities, and the use of web-archives in DH research. As at Stanford, interconnecting with DARIAH Working Groups was of core interest to participants, and a new Working Group was proposed to explore global access and use of digitised historical newspapers. A further important outcome was the agreement to explore collaboration between the U.S.-based “Collections as Data” initiatives and the Heritage Data Reuse Charter in Europe. The third and final workshop in the series took place in March 2019 in Australia, hosted by the National Library of Australia in Canberra. Convened by the Australian Academy of the Humanities (AAH), together with the Australian Research Data Commons (ARDC) and DARIAH, this event was co-located with the Academy’s second annual Humanities, Arts and Culture Data Summit. The first day of the event, targeted at research leadership and policy makers, was intended to explore new horizons for data-driven humanities and arts research, digital cultural collections and research infrastructure. The two subsequent days focused on engaging with a wide variety of communities, including (digital) humanities researchers and cultural heritage professionals. Organised around a series of Knowledge Exchange Sessions, combined with research-led lightning talks, the participants spoke in detail about how big ideas can be implemented practically on the ground. This poster reflects on the key outcomes and future directions arising from these three workshops, and considers what it might look like for DARIAH to be adopted as a fundamental DH infrastructure in a complex variety of international, national, and regional contexts, with diverse funding models, resources, needs, and expectations. One major outcome of all workshops was the shared recognition that, in spite of extensive funding, planning, and goodwill, these workshops were not nearly global enough in their reach: most importantly they were not inclusive of the Global South. Our new DARIAH beyond Europe community has a strong shared commitment to address this gap

Derivation of Multipotent Mesenchymal Precursors from Human Embryonic Stem Cells

BACKGROUND: Human embryonic stem cells provide access to the earliest stages of human development and may serve as a source of specialized cells for regenerative medicine. Thus, it becomes crucial to develop protocols for the directed differentiation of embryonic stem cells into tissue-restricted precursors. METHODS AND FINDINGS: Here, we present culture conditions for the derivation of unlimited numbers of pure mesenchymal precursors from human embryonic stem cells and demonstrate multilineage differentiation into fat, cartilage, bone, and skeletal muscle cells. CONCLUSION: Our findings will help to elucidate the mechanism of mesoderm specification during embryonic stem cell differentiation and provide a platform to efficiently generate specialized human mesenchymal cell types for future clinical applications