512 research outputs found
Antiphase Light and Temperature Cycles Affect PHYTOCHROME B-Controlled Ethylene Sensitivity and Biosynthesis, Limiting Leaf Movement and Growth of Arabidopsis
Modulation of ethylene- and heat-controlled hyponastic leaf movement in Arabidopsis thaliana by the plant defence hormones jasmonate and salicylate
Upward leaf movement (hyponastic growth) is adopted by several plant species including Arabidopsis thaliana, as a mechanism to escape adverse growth conditions. Among the signals that trigger hyponastic growth are, the gaseous hormone ethylene, low light intensities, and supra-optimal temperatures (heat). Recent studies indicated that the defence-related phytohormones jasmonic acid (JA) and salicylic acid (SA) synthesized by the plant upon biotic infestation repress low light-induced hyponastic growth. The hyponastic growth response induced by high temperature (heat) treatment and upon application of the gaseous hormone ethylene is highly similar to the response induced by low light. To test if these environmental signals induce hyponastic growth via parallel pathways or converge downstream, we studied here the roles of Methyl-JA (MeJA) and SA on ethylene- and heat-induced hyponastic growth. For this, we used a time-lapse camera setup. Our study includes pharmacological application of MeJA and SA and biological infestation using the JA-inducing caterpillar Pieris rapae as well as mutants lacking JA or SA signalling components. The data demonstrate that MeJA is a positive, and SA, a negative regulator of ethylene-induced hyponastic growth and that both hormones repress the response to heat. Taking previous studies into account, we conclude that SA is the first among many tested components which is repressing hyponastic growth under all tested inductive environmental stimuli. However, since MeJA is a positive regulator of ethylene-induced hyponastic growth and is inhibiting low light- and heat-induced leaf movement, we conclude that defence hormones control hyponastic growth by affecting stimulus-specific signalling pathways
Credentials, talent and cultural capital: a comparative study of educational elites in England and France
This article examines student accounts of credentials, talent and academic success, against a backdrop of the enduring liberal ideal of an education-based meritocracy. The article also examines Bourdieuâs account of academic qualifications as the dominant source of institutionalised cultural capital, and concludes that it does not adequately account for comparative differences in the social structure of competition and ideological shifts in class (re)production in different national contexts. This analysis is based on an empirical investigation of elite students at Oxford University and Sciences Po in Paris. We investigated how they understand the competition for a livelihood and whether they see themselves as more âtalentedâ than students from non-elite universities. This investigation revealed important similarities and differences between British and French students that have significant sociological implications for the (re)production and legitimation of educational and labour market inequalities
Glass Transition Behavior of Polymer Films of Nanoscopic Dimensions
Glass transition behavior of nanoscopically thin polymer films is
investigated by means of molecular dynamics simulations. A thin polymer film
that is composed of bead-spring model chains and supported on an idealized, fcc
lattice substrate surface is studied in this work.Comment: in review, macromolecule
Presence of anticitrullinated protein antibodies in a large population-based cohort from the Netherlands
Objectives To determine the prevalence of anticitrullinated protein antibodies (ACPAs) and their association with known rheumatoid arthritis (RA) risk factors in the general population. Methods Lifelines is a multidisciplinary prospective population-based cohort study in the Netherlands. Cross-sectional data from 40 136 participants were used. The detection of ACPA was performed by measuring anti-CCP2 on the Phadia-250 analyser with levels >= 6.2 U/mL considered positive. An extensive questionnaire was taken on demographic and clinical information, including smoking, periodontal health and early symptoms of musculoskeletal disorders. RA was defined by a combination of self-reported RA, medication use for the indication of rheumatism and visiting a medical specialist within the last year. Results Of the total 40 136 unselected individuals, 401 (1.0%) had ACPA level >= 6.2 U/mL. ACPA positivity was significantly associated with older age, female gender, smoking, joint complaints, RA and first degree relatives with rheumatism. Of the ACPA-positive participants, 22.4% had RA (15.2% had defined RA according to our criteria and 7.2% self-reported RA only). In participants without RA, 311 (0.8%) were ACPA-positive. In the non-RA group, older age, smoking and joint complaints remained significantly more frequently present in ACPA-positive compared with ACPA-negative participants. Conclusions In this large population-based study, the prevalence of ACPA levels >= 6.2 U/mL was 1.0% for the total group and 0.8% when excluding patients with RA. Older age, smoking and joint complaints were more frequently present in ACPA-positive Lifelines participants. To our knowledge, this study is the largest study to date on ACPA positivity in the general, mostly Caucasian population
Prognostication using SpO(2)/FiO(2) in invasively ventilated ICU patients with ARDS due to COVID-19-Insights from the PRoVENT-COVID study
Background: The SpO(2)/FiO(2) is a useful oxygenation parameter with prognostic capacity in patients with ARDS. We investigated the prognostic capacity of SpO(2)/FiO(2) for mortality in patients with ARDS due to COVID-19. Methods: This was a post-hoc analysis of a national multicenter cohort study in invasively ventilated patients with ARDS due to COVID-19. The primary endpoint was 28-day mortality. Results: In 869 invasively ventilated patients, 28-day mortality was 30.1%. The SpO(2)/FiO(2) on day 1 had no prognostic value. The SpO(2)/FiO(2) on day 2 and day 3 had prognostic capacity for death, with the best cut-offs being 179 and 199, respectively. Both SpO(2)/FiO(2) on day 2 (OR, 0.66 [95%-CI 0.46-0.96]) and on day 3 (OR, 0.70 [95%-CI 0.51-0.96]) were associated with 28-day mortality in a model corrected for age, pH, lactate levels and kidney dysfunction (AUROC 0.78 [0.76-0.79]). The measured PaO2/FiO(2) and the PaO2/FiO(2) calculated from SpO(2)/FiO(2) were strongly correlated (Spearman's r = 0.79). Conclusions: In this cohort of patients with ARDS due to COVID-19, the SpO(2)/FiO(2) on day 2 and day 3 are independently associated with and have prognostic capacity for 28-day mortality. The SpO(2)/FiO(2) is a useful metric for risk stratification in invasively ventilated COVID-19 patients. (C) 2021 The Authors. Published by Elsevier Inc
Disentangling the sources of ionizing radiation in superconducting qubits
Radioactivity was recently discovered as a source of decoherence and correlated errors for the real-world implementation of superconducting quantum processors. In this work, we measure levels of radioactivity present in a typical laboratory environment (from muons, neutrons, and Îł-rays emitted by naturally occurring radioactive isotopes) and in the most commonly used materials for the assembly and operation of state-of-the-art superconducting qubits. We present a GEANT-4 based simulation to predict the rate of impacts and the amount of energy released in a qubit chip from each of the mentioned sources. We finally propose mitigation strategies for the operation of next-generation qubits in a radio-pure environment
Disentangling the sources of ionizing radiation in superconducting qubits
Radioactivity was recently discovered as a source of decoherence and
correlated errors for the real-world implementation of superconducting quantum
processors. In this work, we measure levels of radioactivity present in a
typical laboratory environment (from muons, neutrons, and gamma's emitted by
naturally occurring radioactive isotopes) and in the most commonly used
materials for the assembly and operation of state-of-the-art superconducting
qubits. We develop a GEANT-4 based simulation to predict the rate of impacts
and the amount of energy released in a qubit chip from each of the mentioned
sources. We finally propose mitigation strategies for the operation of
next-generation qubits in a radio-pure environment
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