Search results for "lcsh:Science"
showing 10 items of 2187 documents
Methionine in a protein hydrophobic core drives tight interactions required for assembly of spider silk
2019
Web spiders connect silk proteins, so-called spidroins, into fibers of extraordinary toughness. The spidroin N-terminal domain (NTD) plays a pivotal role in this process: it polymerizes spidroins through a complex mechanism of dimerization. Here we analyze sequences of spidroin NTDs and find an unusually high content of the amino acid methionine. We simultaneously mutate all methionines present in the hydrophobic core of a spidroin NTD from a nursery web spider’s dragline silk to leucine. The mutated NTD is strongly stabilized and folds at the theoretical speed limit. The structure of the mutant is preserved, yet its ability to dimerize is substantially impaired. We find that side chains of…
(Ré)concilier éclairage urbain et environnement nocturne : les enjeux d’une controverse sociotechnique
2014
International audience; Our paper explains the birth of an environmental problem, i.e. light pollution, viewed as a socio-technical controversy. Supported by the actor-network approach, it traces over forty years the conditions of its emergence, transformation and dissemination to local, national and transnational levels and through various professional disciplines. Schematically, “environmentalists” uphold a holistic approach of “nocturnality” and define artificial light as a pollutant. Facing them, the “technicist” defends a segmented approach and defines artificial light as a nuisance. The introduction of this controversy into the political agenda leads to institutional decisions that gr…
Anticipatory postural adjustments during joint action coordination
2019
International audience; There is a current claim that humans are able to effortlessly detect others’ hidden mental state by simply observing their movements and transforming the visual input into motor knowledge to predict behaviour. Using a classical paradigm quantifying motor predictions, we tested the role of vision feedback during a reach and load-lifting task performed either alone or with the help of a partner. Wrist flexor and extensor muscle activities were recorded on the supporting hand. Early muscle changes preventing limb instabilities when participants performed the task by themselves revealed the contribution of the visual input in postural anticipation. When the partner perfo…
A new member of the fusaricidin family – structure elucidation and synthesis of fusaricidin E
2017
Two hitherto unknown fusaricidins were obtained from fermentation broths of three Paenibacillus strains. After structure elucidation based on tandem mass spectrometry and NMR spectroscopy, fusaricidin E was synthesized to confirm the structure and the suggested stereochemistry. The synthesis was based on a new strategy which includes an efficient access to the 15-guanidino-3-hydroxypentadecanoyl (GHPD) side chain from erucamide.
Tuning the Photoresponse of Nano‐Heterojunction: Pressure‐Induced Inverse Photoconductance in Functionalized WO 3 Nanocuboids
2019
S.R. and S.S. contributed equally to this work. This work was mainly supported by the Natural Science Foundation of China (Grant No. 11874076), National Science Associated Funding (NSAF, Grant No. U1530402), and Science Challenging Program (Grant No. TZ2016001). D.E. thanks the financial support from Spanish MINECO under Grant No. MAT2016-75586-C4-1-P and from Generalitat Valenciana under Grant Prometeo/2018/123, EFIMAT. The X-ray diffraction measurements were performed at the BL15U1 station, Shanghai Synchrotron Radiation Facility (SSRF) in China. The HP XAS measurements were performed at 20 ID-C, APS, ANL. APS is supported by DOE-BES, under contract no. DE-AC02-06CH11357. The authors grat…
Enriching primary student teachers’ conceptions about science teaching: Towards dialogic inquirybased teaching
2012
Inquiry-based teaching has been at the heart of science education since it was first outlined in national standards over a decade ago. The general idea behind the inquiry guidelines is that pupils would adopt ways of conducting science, in addition to conceptually learning, thus attaining also the epistemological dimension of science. Although curricula are based on these ideas of inquiry, all too often authentic inquiry is hindered by overly authoritative approaches and teacher directions. To avoid this, the communicational ways in which teachers can encourage pupil reasoning during different phases of inquiry should be explicitly addressed. This paper addresses this gap by introducing a d…
Heritable Epichloë symbiosis shapes fungal but not bacterial communities of plant leaves
2019
Keystone microbial species have driven eco-evolutionary processes since the origin of life. However, due to our inability to detect the majority of microbiota, members of diverse microbial communities of fungi, bacteria and viruses have largely been ignored as keystone species in past literature. Here we tested whether heritable Epichloë species of pooidae grasses modulate microbiota of their shared host plant. peerReviewed
Conjugation with carbon nanotubes improves the performance of mesoporous silicon as Li-ion battery anode
2020
Carbon nanotubes can be utilized in several ways to enhance the performance of silicon-based anodes. In the present work, thermally carbonized mesoporous silicon (TCPSi) microparticles and single-walled carbon nanotubes (CNTs) are conjugated to create a hybrid material that performs as the Li-ion battery anode better than the physical mixture of TCPSi and CNTs. It is found out that the way the conjugation is done has an essential role in the performance of the anode. The conjugation should be made between negatively charged TCPSi and positively charged CNTs. Based on the electrochemical experiments it is concluded that the positive charges, i.e., excess amine groups of the hybrid material i…
Analysis of Social Media Impact on Opportunity Recognition. A Social Networks and Entrepreneurial Alertness Mixed Approach
2020
This paper investigates the effects of social media on entrepreneurial opportunity recognition. Combining the internal and external approaches of opportunity recognition, the study analyzes how social media influences the entrepreneurs in discovering new entrepreneurial opportunities. Structural equation modeling was used in this study, using the variance-based partial least squares (PLS)&ndash
Exposure to Chemical Cues from Predator-Exposed Conspecifics Increases Reproduction in a Wild Rodent
2018
Abstract Predation involves more than just predators consuming prey. Indirect effects, such as fear responses caused by predator presence, can have consequences for prey life history. Laboratory experiments have shown that some rodents can recognize fear in conspecifics via alarm pheromones. Individuals exposed to alarm pheromones can exhibit behavioural alterations that are similar to those displayed by predator-exposed individuals. Yet the ecological and evolutionary significance of alarm pheromones in wild mammals remains unclear. We investigated how alarm pheromones affect the behaviour and fitness of wild bank voles (Myodes glareolus) in outdoor enclosures. Specifically, we compared th…