3,111 research outputs found

    Benthic foraminifera show some resilience to ocean acidification in the northern Gulf of California, Mexico.

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    The version on PEARL: Corrected proofs are Articles in Press that contain the authors' corrections. Final citation details, e.g., volume/issue number, publication year and page numbers, still need to be added and the text might change before final publication. Although corrected proofs do not have all bibliographic details available yet, they can already be cited using the year of online publication and the DOI , as follows: author(s), article title, journal (year), DOIExtensive CO2 vents have been discovered in the Wagner Basin, northern Gulf of California, where they create large areas with lowered seawater pH. Such areas are suitable for investigations of long-term biological effects of ocean acidification and effects of CO2 leakage from subsea carbon capture storage. Here, we show responses of benthic foraminifera to seawater pH gradients at 74-207m water depth. Living (rose Bengal stained) benthic foraminifera included Nonionella basispinata, Epistominella bradyana and Bulimina marginata. Studies on foraminifera at CO2 vents in the Mediterranean and off Papua New Guinea have shown dramatic long-term effects of acidified seawater. We found living calcareous benthic foraminifera in low pH conditions in the northern Gulf of California, although there was an impoverished species assemblage and evidence of post-mortem test dissolution

    Mediating boundaries between knowledge and knowing: ICT and R4D praxis

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    Research for development (R4D) praxis (theory-informed practical action) can be underpinned by the use of Information and Communication Technologies (ICTs) which, it is claimed, provide opportunities for knowledge working and sharing. Such a framing implicitly or explicitly constructs a boundary around knowledge as reified, or commodified ā€“ or at least able to be stabilized for a period of time (first order knowledge). In contrast ā€˜third-generation knowledgeā€™ emphasizes the social nature of learning and knowledge-making; this reframes knowledge as a negotiated social practice, thus constructing a different system boundary. This paper offers critical reflections on the use of a wiki as a data repository and mediating technical platform as part of innovating in R4D praxis. A sustainable social learning process was sought that fostered an emergent community of practice among biophysical and social researchers acting for the first time as R4D co-researchers. Over time the technologically mediated element of the learning system was judged to have failed. This inquiry asks: How can learning system design cultivate learning opportunities and respond to learning challenges in an online environment to support R4D practice? Confining critical reflection to the online learning experience alone ignores the wider context in which knowledge work took place; therefore the institutional setting is also considered

    Coordinated circadian timing through the integration of local inputs in Arabidopsis thaliana.

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    Individual plant cells have a genetic circuit, the circadian clock, that times key processes to the day-night cycle. These clocks are aligned to the day-night cycle by multiple environmental signals that vary across the plant. How does the plant integrate clock rhythms, both within and between organs, to ensure coordinated timing? To address this question, we examined the clock at the sub-tissue level across Arabidopsis thaliana seedlings under multiple environmental conditions and genetic backgrounds. Our results show that the clock runs at different speeds (periods) in each organ, which causes the clock to peak at different times across the plant in both constant environmental conditions and light-dark (LD) cycles. Closer examination reveals that spatial waves of clock gene expression propagate both within and between organs. Using a combination of modeling and experiment, we reveal that these spatial waves are the result of the period differences between organs and local coupling, rather than long-distance signaling. With further experiments we show that the endogenous period differences, and thus the spatial waves, can be generated by the organ specificity of inputs into the clock. We demonstrate this by modulating periods using light and metabolic signals, as well as with genetic perturbations. Our results reveal that plant clocks can be set locally by organ-specific inputs but coordinated globally via spatial waves of clock gene expression

    Porosities of building limestones: using the solid density to assess data quality

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    A good knowledge of the volume-fraction porosity is essential in any technical work on porous materials. In construction materials the porosity is commonly measured by the Archimedes buoyancy method, from which the bulk density of the test specimen is also obtained. The porosity and the bulk density together fix the solid density of the specimen, as only two of the three quantities are independent. The solid density, although rarely discussed, is determined by the mineralogy of the specimen, and therefore can provide a valuable check on the accuracy of porosity and bulk density measurements. Our analysis of published data on calcitic limestones shows that the solid density is generally close to the ideal crystallographic density of calcite. Small deviations can often be traced to variations in mineral composition. However some published porosityā€“density data are inconsistent with the known mineralogy. Deviations which cannot be ascribed to composition may be assumed to arise from measurement errors. We show the value of using the solid density as a quality check on the measured porosity. We recommend that the solid density should always be calculated for this purpose when the Archimedes method is used. This check can be useful also when porosities are measured by helium pycnometry or by mercury intrusion porosimetry

    How liquid are banks : some evidence from the United Kingdom

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    This paper uses quantitative balance sheet liquidity analysis, based upon modified versions of the BCBS 1 and Moodyā€™s 2 models, to provide indicators which would alarm the UK banksā€™ short and long-term liquidity positions respectively. These information will also underpin other research related liquidity risk to banksā€™ lending and performance. Our framework accurately reflect UK banksā€™ liquidity positions under both normal and stress scenarios based on the consistent accounting information under IFRS. It has significant contribution on Basel III liquidity ratios calculation. The study also presents fundamental financial information to facilitate analysis of banksā€™ business models and funding strategies. Using data for the period 2005-2010, we provide evidence that there have been variable liquidity strains across the UK banks in our sample. The estimated results show that Barclays Bank was the only bank to maintain a healthy short-term liquidity position throughout the sample period; while HSBC remained liquid in the short term, in both normal and stress conditions, except in 2008 and 2010. RBS, meanwhile, maintained healthy long-term liquidity positions from 2008 after receiving government injections of capital. And Santander UK was also able to post healthy long-term liquidity positions, except in 2009. However, the other four banks, the Bank of Scotland, Lloyds TSB, Natwest, and Standard Chartered, proved illiquid, on both a short-term and long-term basis, throughout the six-year period, with Natwest being by far the worst performer

    Large CP Violation in B_s Meson Mixing with EDM constraint in Supersymmetry

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    Motivated by the recent measurement of the like-sign dimuon charge asymmetry, we investigate anomalous CP violation in the B_s- bar{B}_s mixing within the supersymmetry. We show that when gluino diagrams dominate supersymmetry contributions, it is very difficult to realize a large B_s- bar{B}_s mixing phase under the constraint from electric dipole moments barring cancellations. This constraint can be ameliorated by supposing superparticles decoupled. In this limit, we find that it is possible to achieve the large CP asymmetry, and the branching ratio of B_s -> mu^+ mu^- tends to become sizable.Comment: 20 pages, 5 figure
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