35 research outputs found
A social-ecological approach to identify and quantify biodiversity tipping points in South America’s seasonal dry ecosystems
ropical dry forests and savannas harbour unique biodiversity and provide critical ES, yet they are under severe pressure globally. We need to improve our understanding of how and when this pressure provokes tipping points in biodiversity and the associated social-ecological systems. We propose an approach to investigate how drivers leading to natural vegetation decline trigger biodiversity tipping and illustrate it using the example of the Dry Diagonal in South America, an understudied deforestation frontier. The Dry Diagonal represents the largest continuous area of dry forests and savannas in South America, extending over three million km² across Argentina, Bolivia, Brazil, and Paraguay. Natural vegetation in the Dry Diagonal has been undergoing large-scale transformations for the past 30 years due to massive agricultural expansion and intensification. Many signs indicate that natural vegetation decline has reached critical levels. Major research gaps prevail, however, in our understanding of how these transformations affect the unique and rich biodiversity of the Dry Diagonal, and how this affects the ecological integrity and the provisioning of ES that are critical both for local livelihoods and commercial agriculture.Fil: Thonicke, Kirsten. Institute for Climate Impact Research ; AlemaniaFil: Langerwisch, Fanny. Institute for Climate Impact Research ; Alemania. Czech University of Life Sciences Prague; República ChecaFil: Baumann, Matthias. Humboldt Universität zu Berlin; Alemania. Technische Universitat Carolo Wilhelmina Zu Braunschweig.; AlemaniaFil: Leitão, Pedro J.. Humboldt Universität zu Berlin; Alemania. Technische Universitat Carolo Wilhelmina Zu Braunschweig.; AlemaniaFil: Václavík, Tomáš. Helmholtz Centre for Environmental Research; Alemania. Palacký University Olomouc; República ChecaFil: Alencar, Anne. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; BrasilFil: Simões, Margareth. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA); BrasilFil: Scheiter, Simon. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA); Brasil. Universidade Federal do Rio de Janeiro; BrasilFil: Langan, Liam. Senckenberg Biodiversity and Climate Research Centre; AlemaniaFil: Bustamante, Mercedes. Universidade do Brasília; BrasilFil: Gasparri, Nestor Ignacio. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Hirota, Marina. Universidade Federal de Santa Catarina; Brasil. Universidade Estadual de Campinas; BrasilFil: Börner, Jan. Universitat Bonn; AlemaniaFil: Rajao, Raoni. Universidade Federal de Minas Gerais; BrasilFil: Soares Filho, Britaldo. Universidade Federal de Minas Gerais; BrasilFil: Yanosky, Alberto. Consejo Nacional de Ciencia y Tecnología; ParaguayFil: Ochoa Quinteiro, José Manuel. Instituto de Investigación de Recursos Biológicos Alexander von Humboldt; ColombiaFil: Seghezzo, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; ArgentinaFil: Conti, Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: de la Vega Leiner, Anne Cristina. Universität Greifswald; Alemani
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Roadmap on commercialization of metal halide perovskite photovoltaics
Perovskite solar cells (PSCs) represent one of the most promising emerging photovoltaic technologies due to their high power conversion efficiency. However, despite the huge progress made not only in terms of the efficiency achieved, but also fundamental understanding of the relevant physics of the devices and issues which affect their efficiency and stability, there are still unresolved problems and obstacles on the path toward commercialization of this promising technology. In this roadmap, we aim to provide a concise and up to date summary of outstanding issues and challenges, and the progress made toward addressing these issues. While the format of this article is not meant to be a comprehensive review of the topic, it provides a collection of the viewpoints of the experts in the field, which covers a broad range of topics related to PSC commercialization, including those relevant for manufacturing (scaling up, different types of devices), operation and stability (various factors), and environmental issues (in particular the use of lead). We hope that the article will provide a useful resource for researchers in the field and that it will facilitate discussions and move forward toward addressing the outstanding challenges in this fast-developing field
The chromatin remodeler p400 ATPase facilitates Rad51-mediated repair of DNA double-strand breaks
DNA damage signaling and repair take place in a chromatin context. Consequently, chromatin-modifying enzymes, including adenosine triphosphate–dependent chromatin remodeling enzymes, play an important role in the management of DNA double-strand breaks (DSBs). Here, we show that the p400 ATPase is required for DNA repair by homologous recombination (HR). Indeed, although p400 is not required for DNA damage signaling, DNA DSB repair is defective in the absence of p400. We demonstrate that p400 is important for HR-dependent processes, such as recruitment of Rad51 to DSB (a key component of HR), homology-directed repair, and survival after DNA damage. Strikingly, p400 and Rad51 are present in the same complex and both favor chromatin remodeling around DSBs. Altogether, our data provide a direct molecular link between Rad51 and a chromatin remodeling enzyme involved in chromatin decompaction around DNA DSBs
Monitoring the stability and degradation mechanisms of perovskite solar cells by in situ and operando characterization
Solar energy technologies are among the most promising renewable energy sources. The massive growth of global solar generating capacity to multi-terawatt scale is now a requirement to mitigate climate change. Perovskite solar cells (PSCs) are one of the most efficient and cost-effective photovoltaic (PV) technologies with efficiencies reaching the 26% mark. They have attracted substantial interest due to their light-harvesting capacity combined with a low cost of manufacturing. However, unsolved questions of perovskite stability are still a concern, challenging the potential of widespread commercialization. Thus, it is imperative to advance in the understanding of the degradation mechanism of PSCs under in situ and operando conditions where variable and unpredictable stressors intervene, in parallel or sequentially, on the device stability. This review aims to debate the advantages behind in situ and operando characterization to complement stability-testing of PV parameters in the strive to achieve competitive stability and reproducibility in PSCs. We consider the impact of applying single and multi-stressors under constant monitoring of alterations observed in PSC components or complete devices. We outline key future research directions to achieve the long-term stability necessary for the successful commercialization of this promising PV technology
Monitoring the stability and degradation mechanisms of perovskite solar cells by in situ and operando characterization
Solar energy technologies are among the most promising renewable energy sources. The massive growth of global solar generating capacity to multi-terawatt scale is now a requirement to mitigate climate change. Perovskite solar cells (PSCs) are one of the most efficient and cost-effective photovoltaic (PV) technologies with efficiencies reaching the 26% mark. They have attracted substantial interest due to their light-harvesting capacity combined with a low cost of manufacturing. However, unsolved questions of perovskite stability are still a concern, challenging the potential of widespread commercialization. Thus, it is imperative to advance in the understanding of the degradation mechanism of PSCs under in situ and operando conditions where variable and unpredictable stressors intervene, in parallel or sequentially, on the device stability. This review aims to debate the advantages behind in situ and operando characterization to complement stability-testing of PV parameters in the strive to achieve competitive stability and reproducibility in PSCs. We consider the impact of applying single and multi-stressors under constant monitoring of alterations observed in PSC components or complete devices. We outline key future research directions to achieve the long-term stability necessary for the successful commercialization of this promising PV technology
An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles
Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42,400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences. © 2021, The Author(s)
Evaluating 10 years of state-funded GP training in GP offices in Switzerland.
BACKGROUND:Switzerland lacks future general practitioners (GPs). Residents who wished to specialize as general practitioners were formerly trained solely in hospital settings. To better prepare and also attract more young doctors to become GPs, the canton of Bern (equivalent to a state) has implemented a partly state-funded vocational training program in GP practices. Our study examines the efficacy of this 10-year program, identifies factors that positively influence residents in their decision to become a GP and the distribution of new GPs in the canton of Bern, who had taken part in the traineeship. METHODS:This cross-sectional survey among all residents, who participated in a traineeship in general practice from 2008 to 2017 in the canton of Bern asked if residents had taken a subsequent career choice as a GP and if so in which region. Residents scored the importance of their traineeship and their mentor's influence on becoming a GP. By using zip codes of work area of respondents already working as GPs and matching it with population census data, we could obtain the distribution of GPs on a per capita basis. RESULTS:Out of 165 residents who participated in a traineeship, 151 (92%) completed our survey. 81% had chosen a career as a GP or were on track to become a GP. Almost half of the participants became GPs in the offices of their mentors or in the area. Our respondents emphasized the importance of their mentors' influence as well as the training program in their decision-making to become a GP. Most mentioned benefits of being a GP were broad field of medical care (37%) and a fulfilling doctor-patient relationship (34%). We could show an increase in GP practices in the canton of Bern, not only in urban but also accordingly in rural areas. CONCLUSIONS:Most residents continued subsequent careers as general practitioners after having completed a GP traineeship, with almost half of them in the region of their training. A vocational training program helped motivating young doctors to become GPs and underserved regions of the canton of Bern to gain new GPs
Inhibition of type 1 fimbriae-mediated Escherichia coli adhesion and biofilm formation by trimeric cluster thiomannosides conjugated to diamond nanoparticles
© The Royal Society of Chemistry 2015. Recent advances in nanotechnology have seen the development of a number of microbiocidal and/or anti-adhesive nanoparticles displaying activity against biofilms. In this work, trimeric thiomannoside clusters conjugated to nanodiamond particles (ND) were targeted for investigation. NDs have attracted attention as a biocompatible nanomaterial and we were curious to see whether the high mannose glycotope density obtained upon grouping monosaccharide units in triads might lead to the corresponding ND-conjugates behaving as effective inhibitors of E. coli type 1 fimbriae-mediated adhesion as well as of biofilm formation. The required trimeric thiosugar clusters were obtained through a convenient thiol-ene >click> strategy and were subsequently conjugated to alkynyl-functionalized NDs using a Cu(I)-catalysed >click> reaction. We demonstrated that the tri-thiomannoside cluster-conjugated NDs (ND-Man3) show potent inhibition of type 1 fimbriae-mediated E. coli adhesion to yeast and T24 bladder cells as well as of biofilm formation. The biofilm disrupting effects demonstrated here have only rarely been reported in the past for analogues featuring such simple glycosidic motifs. Moreover, the finding that the tri-thiomannoside cluster (Man3N3) is itself a relatively efficient inhibitor, even when not conjugated to any ND edifice, suggests that alternative mono- or multivalent sugar-derived analogues might also be usefully explored for E. coli-mediated biofilm disrupting properties.Peer Reviewe
La Part de fiction dans les images documentaires
Ce numéro s'intéresse aux images reconnues comme documentaires (films et photographies) alors même que ces images d'enregistrement sont une interprétation du réel, c'est du côté du récit construit qu'est analysée ici leur médiatisation du réel. Les contraintes techniques, l'exercice d'une subjectivité ( du « créateur ») ou encore le contexte (historique, économique, politique, culturel, etc.) sont autant d'éléments qui jouent, en effet, sur la mise en images du réel. Par ailleurs, ces récits visuels font l'objet a posteriori d'interprétations, lisibles notamment dans la production de discours critiques. Pour analyser ces relations, ces articles de jeunes chercheurs privilégient l'étude de cas grâce au choix d'un évènement et d'un de ses traitements en images. Ce choix méthodologique permet, d'une part, de faire corpus et, d'autre part, de construire des connaissances sur l'histoire des formes visuelles et des représentations, dans la perspective de générer des savoirs d'ordre historique sur le passé