9,321 research outputs found

    Projections of future air quality are uncertain. But which source of uncertainty is most important?

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    Understanding how air pollution events may change in the future is of key importance to decision makers. Multi-model intercomparison projects focusing on atmospheric chemistry and air quality have been performed to inform the latest IPCC assessments. Future anthropogenic emission changes have generally been the foci of such model experiments, envisaged as the dominant driver of future atmospheric composition. The latest model assessments such as AerChemMIP utilize multi-model ensembles but also have limited individual model ensembles which permit different sources of uncertainty to be characterized. The recent study by Fiore et al. (2022, https://doi.org/10.1029/2021JD035985) specifically considers a multi-model and multi-member ensemble approach. It adds to the quantification of uncertainty in future projections through delineating uncertainty due to model diversity and due to internal or natural climate variability within the climate system, for mean and high PM2.5 air pollution events over the Eastern USA in the 21st century. Exploring the separate roles of internal climate variability and model diversity adds further value to the important research issue of quantifying how future anthropogenic climate change impacts air quality. Future multi-model intercomparisons need to balance the additional knowledge gained from research into understanding multiple sources of uncertainty that can inform decision making vs. the resource costs of performing these experiments using Earth System Models with interactive chemistry

    The effect of Holstein-Friesian genotype and feeding system on selected performance parameters of dairy cows on grass-based systems of milk production in Ireland

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    End of project reportThe overall objective of this project was to assess, the effect of strain of Holstein-Friesian dairy cow, pasture-based feed system (FS) and their interaction on animal performance in terms of milk productivity and lactation profile, body weight (BW), body condition score (BCS), feed intake and energy balance (EB), reproductive performance and overall economic profitability

    Capacities of Grassmann channels

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    A new class of quantum channels called Grassmann channels is introduced and their classical and quantum capacity is calculated. The channel class appears in a study of the two-mode squeezing operator constructed from operators satisfying the fermionic algebra. We compare Grassmann channels with the channels induced by the bosonic two-mode squeezing operator. Among other results, we challenge the relevance of calculating entanglement measures to assess or compare the ability of bosonic and fermionic states to send quantum information to uniformly accelerated frames.Comment: 33 pages, Accepted in Journal of Mathematical Physics; The role of the (fermionic) braided tensor product for quantum Shannon theory, namely capacity formulas, elucidated; The conclusion on the equivalence of Unruh effect for bosons and fermions for quantum communication purposes made clear and even more precis

    Correlated Gravitational Wave and Neutrino Signals from General-Relativistic Rapidly Rotating Iron Core Collapse

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    We present results from a new set of 3D general-relativistic hydrodynamic simulations of rotating iron core collapse. We assume octant symmetry and focus on axisymmetric collapse, bounce, the early postbounce evolution, and the associated gravitational wave (GW) and neutrino signals. We employ a finite-temperature nuclear equation of state, parameterized electron capture in the collapse phase, and a multi-species neutrino leakage scheme after bounce. The latter captures the important effects of deleptonization, neutrino cooling and heating and enables approximate predictions for the neutrino luminosities in the early evolution after core bounce. We consider 12-solar-mass and 40-solar-mass presupernova models and systematically study the effects of (i) rotation, (ii) progenitor structure, and (iii) postbounce neutrino leakage on dynamics, GW, and, neutrino signals. We demonstrate, that the GW signal of rapidly rotating core collapse is practically independent of progenitor mass and precollapse structure. Moreover, we show that the effects of neutrino leakage on the GW signal are strong only in nonrotating or slowly rotating models in which GW emission is not dominated by inner core dynamics. In rapidly rotating cores, core bounce of the centrifugally-deformed inner core excites the fundamental quadrupole pulsation mode of the nascent protoneutron star. The ensuing global oscillations (f~700-800 Hz) lead to pronounced oscillations in the GW signal and correlated strong variations in the rising luminosities of antineutrino and heavy-lepton neutrinos. We find these features in cores that collapse to protoneutron stars with spin periods <~ 2.5 ms and rotational energies sufficient to drive hyper-energetic core-collapse supernova explosions. Hence, joint GW + neutrino observations of a core collapse event could deliver strong evidence for or against rapid core rotation. [abridged]Comment: 29 pages, 14 figures. Replaced with version matching published versio

    Plant Oils and Products of Their Hydrolysis as Substrates for Polyhydroxyalkanoate Synthesis

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    Plant oils could provide a sustainable source of carbon for polyhydroxyalkanoate production as they are both renewable and inexpensive. No study to our knowledge has undertaken a comparative study of the use of major European and global commodity plants oils and products of their hydrolysis as substrates for medium chain length polyhydroxyalkanoate (mcl-PHA) production. There have been several studies which have investigated the use of plant oils and their hydrolysis products for short chain length PHA (scl-PHA) production, therefore, in this study, we have focused specifically on mcl-PHA-producing organisms. A comparison between direct growth on oils and the products of their hydrolysis is described here for several mcl-PHA-producing Pseudomonas strains. Pseudomonas putida KT2440, CA-3, GO16, Pseudomonas chlororaphis 555 were screened for their ability to utilize a range of common plant oils (olive, sunflower, rapeseed, and palm) and their hydrolysis products as sole sources of carbon and energy for growth and PHA accumulation. When the oils were supplied in shaken flask experiments, P. putida CA-3 and P. putida KT2440 showed little or no growth, while P. putida GO16 reached a cell dry weight of between 0.33 and 0.56 g L–1, and accumulated mcl-PHA to between 12 and 25 % of CDW, P. chlororaphis 555 reached a cell dry weight of between 0.67 and 0.86 g L–1, and accumulated mcl-PHA to between 27 and 34 % CDW in 48 h. In contrast, when the hydrolyzed fatty acid mixtures were supplied, all 4 strains tested grew and accumulated mcl-PHA. P. putida CA-3 and GO16 achieved the highest biomass (1.02 – 1.06 g L–1) with the majority of the hydrolyzed plant oil fatty acids, however P. chlororaphis 555 accumulated similar levels of PHA as these two strains. Despite being the strain of choice for mcl-PHA accumulation, for the majority of studies, P. putida KT2440 achieved less biomass and accumulated less PHA than other strains tested with the majority of oil-derived fatty acids. It is important to note that both biomass and PHA levels varied significantly across strain and hydrolyzed oil type. Due to the fact that P. chlororaphis 555 was able to grow and accumulate PHA from both plant oils and hydrolyzed oil fatty acids, it was selected for bioreactor trials to try to achieve high cell density and high PHA productivity using rapeseed oil and hydrolyzed rapeseed oil fatty acids. Rapeseed oil (RO) and its hydrolysis product (HROFA) were chosen for these experiments because P. chlororaphis 555 accumulated approximately 30 % mcl-PHA from both substrates, and as this oil can be produced globally, it would offer less barriers to scale-up than Palm oil. The mcl-PHA volumetric productivity with RO as the substrate was 0.53 g L–1 h–1 after 25 h with a yield of 0.22 g PHA g–1 oil, while the volumetric productivity with HROFA as the substrate was 0.54 g L–1 h–1 after 25 h with again a lower yield of 0.15 g PHA g–1 HROFA. Thus, under the fermentation conditions tested, HROFA was an inferior substrate for PHA production when compared to RO

    What factors are most influential in increasing cervical cancer screening attendance? An online study of UK-based women1

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    Objective: Cervical cancer is the fourth most commonly occurring cancer in women worldwide. The UK has one of the highest cervical screening rates in Europe, yet attendance has been decreasing. This study aimed to identify barriers and facilitators to screening attendance and assess the perceived importance of these factors. Methods: 194 women living in the UK were recruited via an online research recruitment website to an online survey. Most participants (N = 128, 66.0%) were currently up-to-date with cervical screening, 66 participants (34.0%) had never been screened, or were overdue for screening. Participants identified barriers and facilitators to cervical screening attendance via free-text responses and were also asked to rate a list of factors as most to least influential over decision making. Results were analysed using thematic content analysis and ratings analysed using multivariable analyses. Results: The most commonly reported barriers were: Pain/discomfort; Embarrassment; and Time. These were also rated as most influential for decision making. The most commonly reported facilitators were: Ease of making appointments; Peace of mind; and Fear of cancer/preventing serious illness. While importance rating of barriers did not differ by previous screening behaviour, ratings of some facilitators significantly differed. Up-to-date women rated believing screening is potentially life-saving and part of personal responsibility as significantly more important than overdue/never screened women. Conclusion: This study confirmed that factors which encourage screening are key to the decision of whether to attend screening. Women suggested several improvements that might make attending easier and improve uptake, including flexibility of screening locations to fit around work hours and childcare arrangements. Psychological facilitators included the peace of mind that screening brings and the belief that cervical cancer screening is potentially life-saving. Public health interventions should target factors which facilitate screening and how these interplay with barriers in order to improve uptake

    Identifying and mitigating residual vibrations in wave-based control of lumped, flexible systems

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Wave-based control (WBC) is a technique for motion control of under-actuated flexible sys-tems. It envisages actuator motion as launching a motion wave into the system, while simulta-neously absorbing any wave returning from the system. For rest-to-rest motion the net launch displacement is set at half the target displacement. In absorbing the returning wave and vibra-tions, WBC moves the system the remaining distance to the target, with zero steady-state error. The focus of this paper is on very small residual vibrations around the target position which can endure for a long time after arrival at target. This issue was discovered through a recent devel-opment within WBC context on controlling complex two-dimensional, mass-spring, beam-like arrays. To date their existence has been unidentified. This paper investigates and interprets the nature of these vibrations, explains and identifies them based on wave ideas, and finally offers a new wave-based approach to mitigate or suppress them. It also discusses their implication, not just for WBC but for the general problem of control of flexible systems
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