3,052 research outputs found
The ocean carbon sink – impacts, vulnerabilities and challenges
Carbon dioxide (CO2) is, next to water vapour, considered to be the most important natural greenhouse gas on Earth. Rapidly rising atmospheric CO2 concentrations caused by human actions such as fossil fuel burning, land-use change or cement production over the past 250 years have given cause for concern that changes in Earth’s climate system may progress at a much faster pace and larger extent than during the past 20 000 years. Investigating global carbon cycle pathways and finding suitable adaptation and mitigation strategies has, therefore, become of major concern in many research fields. The oceans have a key role in regulating atmospheric CO2 concentrations and currently take up about 25% of annual anthropogenic carbon emissions to the atmosphere. Questions that yet need to be answered are what the carbon uptake kinetics of the oceans will be in the future and how the increase in oceanic carbon inventory will affect its ecosystems and their services. This requires comprehensive investigations, including high-quality ocean carbon measurements on different spatial and temporal scales, the management of data in sophisticated databases, the application of Earth system models to provide future projections for given emission scenarios as well as a global synthesis and outreach to policy makers. In this paper, the current understanding of the ocean as an important carbon sink is reviewed with respect to these topics. Emphasis is placed on the complex interplay of different physical, chemical and biological processes that yield both positive and negative air–sea flux values for natural and anthropogenic CO2 as well as on increased CO2 (uptake) as the regulating force of the radiative warming of the atmosphere and the gradual acidification of the oceans. Major future ocean carbon challenges in the fields of ocean observations, modelling and process research as well as the relevance of other biogeochemical cycles and greenhouse gases are discussed
The effect of berberine supplementation on obesity parameters, inflammation and liver function enzymes: A systematic review and meta-analysis of randomized controlled trials
Introduction: So far, no study has summarized the findings on the effects of berberine intake on anthropometric parameters, C-reactive protein (CRP) and liver enzymes. This systematic review and meta-analysis were done based upon randomized controlled trials (RCTs) to analyze the effects of berberine on anthropometric parameters, CRP and liver enzymes. Method: Following databases were searched for eligible studies published from inception to 30 July 2019: MEDLINE, EMBASE, Web of Science, Cochrane Library, PubMed and Google scholar. Necessary data were extracted. Data were pooled by the inverse variance method and expressed as mean difference with 95 Confidence Intervals (95 CI). Result: 12 studies were included. Berberine treatment moderately but significantly decreased body weight (WMD = �2.07 kg, 95 CI -3.09, �1.05, P < 0.001), body mass index (BMI) (WMD = �0.47 kg/m2, 95 CI -0.70, �0.23, P < 0.001), waist circumference (WC) (WMD = �1.08 cm, 95 CI -1.97, �0.19, P = 0.018) and C-reactive protein (CRP) concentrations (WMD = �0.42 mg/L, 95 CI -0.82, �0.03, P = 0.034). However, berberine intake did not affect liver enzymes, including alanine aminotransferase (ALT) (WMD = �1.66 I/U, 95 CI -3.98, 0.65, P = 0.160) and aspartate aminotransferase (AST) (WMD = �0.87 I/U, 95 CI -2.56, 0.82, P = 0.311). Conclusion: This meta-analysis found a significant reduction of body weight, BMI, WC and CRP levels associated with berberine intake which may have played an indirect role in improved clinical symptoms in diseases with metabolic disorders. Berberine administration had no significant effect on ALT and AST levels. © 2020 European Society for Clinical Nutrition and Metabolis
Postmarketing nutrivigilance safety profile: A line of dietary food supplements containing red yeast rice for dyslipidemia
Introduction: In the absence of a European standardized postmarketing food supplement surveillance system (nutrivigilance), some member states and companies have developed their own approaches to monitoring potential adverse reactions to secure a high level of product safety. This paper describes the use of a nutrivigilance system in monitoring the incidence of spontaneously reported suspected adverse reactions associated with food supplements containing red yeast rice (RYR). Material and methods: We report the data from a widely used product marketed under the trademark Armolipid/Armolipid Plus. Postmarketing information was collected in a voluntary nutrivigilance system established by the manufacturing company (Meda Pharma SpA, a Viatris Company, Monza, Italy). From 1st October 2004 to 31st December 2019, this system captured cases of suspected adverse reactions spontaneously reported by consumers, healthcare professionals, health authorities, regardless of causality. Results: The total number of case reports received mentioning the RYR food supplement product line was 542, in which 855 adverse events (AEs) were reported. The total reporting rate of AEs was estimated to be 0.037% of 2,287,449 exposed consumers. Of the 542 cases, 21 (0.0009% of exposed consumers) included suspected serious adverse events (SAEs). After careful investigation, 6 cases (0.0003% of consumers exposed) and 6 AEs were assessed by the manufacturer as serious and potentially related to exposure to the above-mentioned RYR-based nutraceutical. Conclusions: This nutrivigilance-derived data analysis clearly demonstrates a low prevalence of suspected adverse events associated with the red yeast rice product line. Consumer safety of food supplements could be generally improved by raising awareness of the importance of following the indications and warnings detailed in a food supplement's labeling
Lyashko-Looijenga morphisms and submaximal factorisations of a Coxeter element
When W is a finite reflection group, the noncrossing partition lattice NCP_W
of type W is a rich combinatorial object, extending the notion of noncrossing
partitions of an n-gon. A formula (for which the only known proofs are
case-by-case) expresses the number of multichains of a given length in NCP_W as
a generalised Fuss-Catalan number, depending on the invariant degrees of W. We
describe how to understand some specifications of this formula in a case-free
way, using an interpretation of the chains of NCP_W as fibers of a
Lyashko-Looijenga covering (LL), constructed from the geometry of the
discriminant hypersurface of W. We study algebraically the map LL, describing
the factorisations of its discriminant and its Jacobian. As byproducts, we
generalise a formula stated by K. Saito for real reflection groups, and we
deduce new enumeration formulas for certain factorisations of a Coxeter element
of W.Comment: 18 pages. Version 2 : corrected typos and improved presentation.
Version 3 : corrected typos, added illustrated example. To appear in Journal
of Algebraic Combinatoric
The Current State of Climate Change Perceptions and Policies in Vietnam: 2014 Report
This report was constructed to assess the current perceptions and policies regarding climate change in Vietnam. The report comprises a country report, outlining current policies relating to climate change, stakeholder mapping regarding climate change locally and nationally, and results from two stakeholder perception surveys conducted locally and nationally in Vietnam. A total of 50 stakeholders were interviewed, 25 locally and 25 nationally. The stakeholders in the survey represented government offices, universities, research institutions, NGOs, and farmers’ groups. Concerns about climate change impacts included drought, flooding, rainfall variation, and salinity intrusion. These concerns, as well as the methods in which stakeholders would like to receive climate information, varied between local and national stakeholders as well as by the type of institution that the stakeholder represented. This emphasizes a need for location- and user-specific responses to climate change
Media representation of regulated incivilities: Relevant actors, problems, solutions and the role played by experts in the Flemish press
This article analyses the representations of regulated nuisance in a section of Flemish newspapers over time. It identifies the groups of people who have been successful in conveying messages in and through Flemish press news, and explores the way they have represented problems of, and suggested solutions to, regulated incivilities over the years. Furthermore, against the backdrop of newsmaking criminology, it considers whether and how crime and justice experts have contributed to shaping the Flemish media discourse on regulated incivilities over time. Overall the analysis of press news has found that the press, by giving coverage to the voices of local institutional actors, has promoted the criminalization of nuisance and, especially, of physical incivilities. The views of criminological experts, by contrast, have remained marginal. The article concludes by suggesting how such findings present a new set of empirical and conceptual challenges for newsmaking criminology, and more generally, for public criminology
Impact of circulation on export production, dissolved organic matter and dissolved oxygen in the ocean: Results from OCMIP-2
Impact of measurement backaction on nuclear spin qubits in silicon
Phosphorus donor nuclear spins in silicon couple weakly to the environment
making them promising candidates for high-fidelity qubits. The state of a donor
nuclear spin qubit can be manipulated and read out using its hyperfine
interaction with the electron confined by the donor potential. Here we use a
master equation-based approach to investigate how the backaction from this
electron-mediated measurement affects the lifetimes of single and multi-donor
qubits. We analyze this process as a function of electric and magnetic fields,
and hyperfine interaction strength. Apart from single nuclear spin flips, we
identify an additional measurement-related mechanism, the nuclear spin
flip-flop, which is specific to multi-donor qubits. Although this flip-flop
mechanism reduces qubit lifetimes, we show that it can be effectively
suppressed by the hyperfine Stark shift. We show that using atomic precision
donor placement and engineered Stark shift, we can minimize the measurement
backaction in multi-donor qubits, achieving larger nuclear spin lifetimes than
single donor qubits
The osmotic pressure of charged colloidal suspensions: A unified approach to linearized Poisson-Boltzmann theory
We study theoretically the osmotic pressure of a suspension of charged
objects (e.g., colloids, polyelectrolytes, clay platelets, etc.) dialyzed
against an electrolyte solution using the cell model and linear
Poisson-Boltzmann (PB) theory. From the volume derivative of the grand
potential functional of linear theory we obtain two novel expressions for the
osmotic pressure in terms of the potential- or ion-profiles, neither of which
coincides with the expression known from nonlinear PB theory, namely, the
density of microions at the cell boundary. We show that the range of validity
of linearization depends strongly on the linearization point and proof that
expansion about the selfconsistently determined average potential is optimal in
several respects. For instance, screening inside the suspension is
automatically described by the actual ionic strength, resulting in the correct
asymptotics at high colloid concentration. Together with the analytical
solution of the linear PB equation for cell models of arbitrary dimension and
electrolyte composition explicit and very general formulas for the osmotic
pressure ensue. A comparison with nonlinear PB theory is provided. Our analysis
also shows that whether or not linear theory predicts a phase separation
depends crucially on the precise definition of the pressure, showing that an
improper choice could predict an artificial phase separation in systems as
important as DNA in physiological salt solution.Comment: 16 pages, 5 figures, REVTeX4 styl
Using conceptual metaphor and functional grammar to explore how language used in physics affects student learning
This paper introduces a theory about the role of language in learning
physics. The theory is developed in the context of physics students' and
physicists' talking and writing about the subject of quantum mechanics. We
found that physicists' language encodes different varieties of analogical
models through the use of grammar and conceptual metaphor. We hypothesize that
students categorize concepts into ontological categories based on the
grammatical structure of physicists' language. We also hypothesize that
students over-extend and misapply conceptual metaphors in physicists' speech
and writing. Using our theory, we will show how, in some cases, we can explain
student difficulties in quantum mechanics as difficulties with language.Comment: Accepted for publication in Phys. Rev. ST:PE
- …