209 research outputs found
Plasticity in the proteome of Emiliania huxleyi CCMP 1516 to extremes of light is highly targeted
No full textSummary
Optimality principles are often applied in theoretical studies of microalgal ecophysiology to predict changes in allocation of resources to different metabolic pathways, and optimal acclimation is likely to involve changes in the proteome, which typically accounts for > 50% of cellular nitrogen (N).
We tested the hypothesis that acclimation of the microalga Emiliania huxleyi CCMP 1516 to suboptimal vs supraoptimal light involves large changes in the proteome as cells rebalance the capacities to absorb light, fix CO2, perform biosynthesis and resist photooxidative stress.
Emiliania huxleyi was grown in nutrient‐replete continuous culture at 30 (LL) and 1000 μmol photons m−2 s−1 (HL), and changes in the proteome were assessed by LC‐MS/MS shotgun proteomics. Changes were most evident in proteins involved in the light reactions of photosynthesis; the relative abundance of photosystem I (PSI) and PSII proteins was 70% greater in LL, light‐harvesting fucoxanthin–chlorophyll proteins (Lhcfs) were up to 500% greater in LL and photoprotective LI818 proteins were 300% greater in HL.
The marked changes in the abundances of Lhcfs and LI818s, together with the limited plasticity in the bulk of the E. huxleyi proteome, probably reflect evolutionary pressures to provide energy to maintain metabolic capabilities in stochastic light environments encountered by this species in nature.
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The trade-off between the light-harvesting and photoprotective functions of fucoxanthin-chlorophyll proteins dominates light acclimation in Emiliania huxleyi (clone CCMP 1516)
No full textMechanistic understanding of the costs and benefits of photoacclimation requires knowledge of how photophysiology is affected by changes in the molecular structure of the chloroplast.We tested the hypothesis that changes in the light dependencies of photosynthesis, nonphotochemical quenching and PSII photoinactivation arises from changes in the abundances of chloroplast proteins in Emiliania huxleyi strain CCMP 1516 grown at 30 (Low Light; LL) and 1000 (High Light; HL) µmol photons m-2 s-1 photon flux densities.Carbon-specific light-saturated gross photosynthesis rates were not significantly different between cells acclimated to LL and HL. Acclimation to LL benefited cells by increasing biomass-specific light absorption and gross photosynthesis rates under low light, whereas acclimation to HL benefited cells by reducing the rate of photoinactivation of PSII under high light. Differences in the relative abundances of proteins assigned to light-harvesting (Lhcf), photoprotection (LI818-like), and the photosystem II (PSII) core complex accompanied differences in photophysiology: specifically, Lhcf:PSII was greater under LL, whereas LI818:PSII was greater in HL.Thus, photoacclimation in E. huxleyi involved a trade-off amongst the characteristics of light absorption and photoprotection, which could be attributed to changes in the abundance and composition of proteins in the light-harvesting antenna of PSII
Statistical analysis plan for the second INTEnsive blood pressure Reduction in Acute Cerebral hemorrhage Trial (INTERACT2): a large-scale investigation to solve longstanding controversy over the most appropriate management of elevated blood pressure in the hyperacute phase of intracerebral hemorrhage
No full textCraig Anderson, Emma Heeley, Stephane Heritier, Hisatomi Arima, Mark Woodward, Richard Lindley, Bruce Neal, Yining Huang, Ji-Guang Wang, Mark Parsons, Christian Stapf, Tom Robinson, Pablo Lavados, Candice Delcourt, Stephen Davis, and John Chalmers for the INTERACT2 Investigator
Anisotropy of permeability in faulted porous sandstones
No full textThank you to Total E & P UK for funding the project, and especially Chris Wibberley, Claude Gout and Stephane Vignau for input. The author would also like to thank Zoe Shipton and Graham Yielding for their constructive reviews of the manuscript. Thanks also to Manuel Prieto for sharing his MSc pilot study written at the University of Aberdeen, Professor Martin Lee and Peter Chung at the University of Glasgow for SEM use and lastly thank you to Gavin Tennent for access to the Clashach Quarry and for samples.Peer reviewe
Alloprof: a new French question-answer education dataset and its use in an information retrieval case study
No full textTeachers and students are increasingly relying on online learning resources
to supplement the ones provided in school. This increase in the breadth and
depth of available resources is a great thing for students, but only provided
they are able to find answers to their queries. Question-answering and
information retrieval systems have benefited from public datasets to train and
evaluate their algorithms, but most of these datasets have been in English text
written by and for adults. We introduce a new public French question-answering
dataset collected from Alloprof, a Quebec-based primary and high-school help
website, containing 29 349 questions and their explanations in a variety of
school subjects from 10 368 students, with more than half of the explanations
containing links to other questions or some of the 2 596 reference pages on the
website. We also present a case study of this dataset in an information
retrieval task. This dataset was collected on the Alloprof public forum, with
all questions verified for their appropriateness and the explanations verified
both for their appropriateness and their relevance to the question. To predict
relevant documents, architectures using pre-trained BERT models were fine-tuned
and evaluated. This dataset will allow researchers to develop
question-answering, information retrieval and other algorithms specifically for
the French speaking education context. Furthermore, the range of language
proficiency, images, mathematical symbols and spelling mistakes will
necessitate algorithms based on a multimodal comprehension. The case study we
present as a baseline shows an approach that relies on recent techniques
provides an acceptable performance level, but more work is necessary before it
can reliably be used and trusted in a production setting
Development and initial validation of the Falls Efficacy Scale International (FES-I).
No full textBackground: there is a need for a measure of fear of falling that assesses both easy and difficult physical activities and social activities and is suitable for use in a range of languages and cultural contexts, permitting direct comparison between studies and populations in different countries and settings. Objective: to develop a modified version of the Falls Efficacy Scale to satisfy this need, and to establish its psychometric properties, reliability, and concurrent validity (i.e. that it demonstrates the expected relationship with age, falls history and falls risk factors). Design: cross-sectional survey. Setting: community sample. Method: 704 people aged between 60 and 95 years completed The Falls Efficacy Scale-International (FES-I) either in postal self-completion format or by structured interview. Results: the FES-I had excellent internal and test–retest reliability (Cronbach’s =0.96, ICC=0.96). Factor analysis suggested a unitary underlying factor, with two dimensions assessing concern about less demanding physical activities mainly in the home, and concern about more demanding physical activities mainly outside the home. The FES-I had slightly better power than the original FES items to discriminate differences in concern about falling between groups differentiated by sex, age, occupation, falls in the past year, and falls risk factors (chronic illness, taking multiple or psychoactive medications, dizziness). Conclusions: the FES-I has close continuity with the best existing measure of fear of falling, excellent psychometric properties, and assesses concerns relating to basic and more demanding activities, both physical and social. Further research is required to confirm cross-cultural and predictive validity
Study of the B+c → J/ψD+s and B+c → J/ψD*s+ decays with the ATLAS detector
No full textThe decays B-c(+) -> J/psi D-s(+) and B-c(+) -> J/psi D-s*(+) are studied with the ATLAS detector at the LHC using a dataset corresponding to integrated luminosities of 4.9 and 20.6 fb(-1) of pp collisions collected at centre-of-mass energies root s = 7 TeV and 8 TeV, respectively. Signal candidates are identified through J/psi -> mu(+)mu(-) and D-s(()*()+) -> phi pi(+)(gamma/pi(0)) decays. With a two-dimensional likelihood fit involving the B-c(+) reconstructed invariant mass and an angle between the mu(+) and D-s(+) candidate momenta in the muon pair rest frame, the yields of B-c(+) -> J/psi D-s(+) and B-c(+) -> J/psi D-s*(+), and the transverse polarisation fraction in B-c(+) -> J/psi D-s*(+) decay are measured. The transverse polarisation fraction is determined to be Gamma +/-+/-(B-c(+) -> J/psi D-s*(+))/Gamma(B-c(+) -> J/psi D-s*(+)) = 0.38 +/- 0.23 +/- 0.07, and the derived ratio of the branching fractions of the two modes is B-Bc+ -> J/psi D-s*+/B-Bc+ -> J/psi D-s(+) = 2.8(-0.8)(+1.2) +/- 0.3, where the first error is statistical and the second is systematic. Finally, a sample of B-c(+) -> J/psi pi(+) decays is used to derive the ratios of branching fractions B-Bc+ -> J/psi D-s*+/B-Bc+ -> J/psi pi(+) = 3.8 +/- 1.1 +/- 0.4 +/- 0.2 and B-Bc+ -> J/psi D-s*+/B-Bc+ -> J/psi pi(+) = 10.4 +/- 3.1 +/- 1.5 +/- 0.6, where the third error corresponds to the uncertainty of the branching fraction of D-s(+) -> phi(K+ K-)pi(+) decay. The available theoretical predictions are generally consistent with the measurement.ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1140/epjc/s10052-015-3743-8</p
Hypothermia as an adjuvant treatment in paediatric refractory or super-refractory status epilepticus
No full textInternational audienceTherapeutic hypothermia is among the adjuvant therapies suggested for refractory or super-refractory status epilepticus (R/SR-SE) in paediatric patients. Experimental evidence of neuroprotective and antiseizure effects provides a strong rationale for using therapeutic hypothermia in patients with status epilepticus. Thus, hypothermia between 20°C and 33°C in animals with status epilepticus is associated not only with significantly less neuronal damage, predominantly in the hippocampal CA1, CA2, and CA3 areas, but also with increased seizure latency and decreased seizure frequency and duration. Therapeutic hypothermia has rarely been used in paediatric R/SR-SE. In the few reported cases, seizure control was markedly improved but nearly half the patients experienced recurrences after rewarming. Studies are needed to clarify the modalities and indications of therapeutic hypothermia in paediatric patients with R/SR-SE. What this paper adds: Hypothermia at 20°C to 33°C is neuroprotective and has antiseizure effects in experimental status epilepticus. In children, antiseizure effects are marked but recurrences after rewarming are common
Orbital chronology of the Pliensbachian - Toarcian transition from the Central High Atlas Basin (Morocco)
No full textInternational audienceThe Pliensbachian-Toarcian transition has been studied in depth for the major environmental changes and the marine invertebrate biodiversity crisis observed at that time. Despite a large number of studies performed, the time frames provided for this interval show large discrepancies from author to author. Major environmental changes occurring at that time impacted the sedimentation pattern and sedimentation rates, making uncertain the construction of time scales. Here, we provide a new astrochronological framework based on an expanded hemipelagic section from the Central High Atlas Basin (Morocco). delta C-13 and CaCO3 measurements performed on the studied section allowed the construction of an orbital time scale based on the 405-kyr eccentricity and the obliquity cycles. This orbital time scale is then compared to the Peniche section (GSSP of the Toarcian Stage) in order to limit the effects of eventual condensation and erosion events on the construction of the orbital time scale. The duration of the early Toarcian Polymorphum Zone is then assessed at 0.9-1.0 myr, while the interval from the base of the Toarcian Stage to the FO of C. superbus is assessed at 0.51 myr. This long duration of the Polymorphum Zone highlights the fact that numerous sections in Europe are affected by long-term condensation and hiati around the Pliensbachian Toarcian transition. Finally, we also explore the potential of the Central High Atlas basin to provide a refined time scale for the late Pliensbachian. Preliminary data lead to a duration assessment of the NJ5b calcareous nannofossil zone of at least 2.07 myr, and to a mean duration of the Emaciatum ammonite zone of 2.05 myr. These durations are similar to 1 myr longer than the durations proposed in the Geological Time Scale 2012, which illustrates the potential of the Central High Atlas Basin for calibrating the Pliensbachian times
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