922017 research outputs found
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Young children rely on gossip when jointly reasoning about whom to believe
No full textPeople rely on reputational information communicated via gossip when deciding about with whom to cooperate, whom to believe, and whom to trust. In two studies, we investigated whether 5 and 7-yearold children trust in gossip when determining a course of action. In Study 1, 5 and 7-year-old Germanspeaking peer dyads (N = 64 dyads, 32 female dyads) were presented with a collaborative problem-solving task (e.g., deciding together what a creature eats). Each child individually received conflicting information about the solution from a different informant (e.g., one proposed rocks; the other proposed sand). Each child additionally heard gossip about the informant’s reputation: one informant had a good reputation; the other had a bad reputation. In the experimental condition, the reputation was relevant to the task (honesty), whereas it was irrelevant in the control condition (tidiness). Seven-year-old dyads, and 5-year-old dyads to a lesser extent, settled on the items suggested by the informant with good reputation in the experimental but not in the control condition. Only 7-year-old children explicitly referred to the information conveyed via gossip, engaging in metatalk about the reputations of the informants. In Study 2, we replicated these findings in a more controlled experiment in which 5 and 7-year-old American English-speaking children (N = 48, 27 girls) tried to convince an adult partner who proposed the item suggested by the informant with bad reputation. Thus, starting around age 5, and more reliably at age 7, children selectively rely on gossip in identifying trustworthy individuals in their collaborative reasoning with partners.</p
Making History Together: The UK’s National Health Service and the story of our lives since 1948
No full textOnly since the 2010s have historians become interested in dimensions of the UK’s National Health Service (NHS) histories beyond institutional, policy, and political narratives and the seventieth anniversary of the Service in 2018 gave additional impetus to work in this area. This paper argues for the need for a new interpretative framework for NHS histories that better reflects its multiple identities and social meanings. Drawing on a UK-wide programme of work it explores the processes of creating digital archive of NHS history using concepts and methodologies that foreground the institution’s social and dynamic nature and are underpinned by a commitment to inclusivity of perspectives and actors. It considers the challenges of working across academic, health, and heritage sectors and the need for historians to adapt to sharing power and agency when working alongside volunteers and interviewees. It concludes that the history produced through these ways of working is rich and insightful and has the potential to reshape historical practice and scholarship around NHS histories and beyond
Nanoparticle transport within non-Newtonian fluid flow in porous media
No full textControl over dispersion of nanoparticles in polymer solutions through porous media is important for subsurface applications such as soil remediation and enhanced oil recovery. Dispersion is affected by the spatial heterogeneity of porous media, the non-Newtonian behavior of polymer solutions, and the Brownian motion of nanoparticles. Here, we use the Euler-Lagrangian method to simulate the flow of nanoparticles and inelastic non-Newtonian fluids (described by Meter model) in a range of porous media samples and injection rates. In one case, we use a fine mesh of more than 3 million mesh points to model nanoparticles transport in a sandstone sample. The results show that the velocity distribution of nanoparticles in the porous medium is non-Gaussian, which leads to the non-Fickian behaviour of nanoparticles dispersion. Due to pore space confinement, the longtime mean square displacement of nanoparticles depends nonlinearly on time. Additionally the gradient of shear stress in the pore-space of the porous medium dictates the transport behaviour of nanoparticles in the porous medium. Furthermore, the Brownian motion of nanoparticles increases the dispersion of nanoparticles along the longitudinal and transverse direction
Multi-objective QUBO Solver: Bi-objective Quadratic Assignment Problem
No full textQuantum and quantum-inspired optimisation algorithms are designed to solve problems represented in binary, quadratic and unconstrained form. Combinatorial optimisation problems are therefore often formulated as Quadratic Unconstrained Binary Optimisation Problems (QUBO) to solve them with these algorithms. Moreover, these QUBO solvers are often implemented using specialised hardware to achieve enormous speedups, e.g. Fujitsu’s Digital Annealer (DA) and D-Wave’s Quantum Annealer. However, these are single-objective solvers, while many real-world problems feature multiple conflicting objectives. Thus, a common practice when using these QUBO solvers is to scalarise such multi-objective problems into a sequence of single-objective problems. Due to design trade-offs of these solvers, formulating each scalarisation may require more time than finding a local optimum.We present the first attempt to extend the algorithm supporting a commercial QUBO solver as a multi-objective solver that is not based on scalarisation. The proposed multi-objective DA algorithm is validated on the bi-objective Quadratic Assignment Problem. We observe that algorithm performance significantly depends on the archiving strategy adopted, and that combining DA with non-scalarisation methods to optimise multiple objectives outperforms the current scalarised version of the DA in terms of final solution quality
Rifting and recharge as triggers of the mixed basalt-1 rhyolite Halarauður ignimbrite eruption (Krafla, Iceland)
No full textWe present a petrologic study of the ca. 110 ka Halarauður eruption (7 ± 6 km3 magma), associated with collapse of Krafla caldera in northeast Iceland. Whole-rock compositions of juvenile Halarauður products span a continuous range between quartz tholeiite basalt (50.0 wt% SiO2, 5.0 wt% MgO; Mg# 42) and rhyolite (74.6 wt% SiO2). Linear correlations between all major elements are consistent with two-component mixing of subequal volumes of these endmember magmas, whereas correlations between trace elements are influenced by diffusive fractionation during chaotic mixing. Evolved compositions (andesite to rhyolite) and compositional heterogeneity are typical of early-erupted units, reflecting tapping of the upper, more silicic regions of a compositionally heterogeneous reservoir undergoing chaotic mixing. Later-erupted deposits are more compositionally homogeneous and grade smoothly upward from andesite to basalt, reflecting tapping of denser hybrid magma and uncontaminated basalt from lower in the chamber. All erupted products host <1-2 modal% macrocrysts, implying storage at near-liquidus temperatures. Geobarometry and MELTS modeling suggest shallow storage pressures of ~200 MPa (~8 km depth) for the quartz tholeiite. Plagioclase (An60-76) and augite (Mg# 68-75) macrocrysts crystallized from this basalt during shallow storage, while sparse glomerocrysts (plagioclase ± augite ± olivine ± orthopyroxene) in late-erupted basaltic material are derived from disaggregated cumulate mush and include more primitive compositions. Occasional narrow sodic rims on plagioclase crystals from the quartz tholeiite record short periods of re-equilibration with hybrid magmas during mixing, constrained by experimental growth rates as at most two months and possibly as short as tens of hours. A second population of calcic plagioclase (cores An83-91) with adhering primitive basaltic glass selvages (Mg# 53-59) occurs sparsely in deposits of the first eruptive phase and is scarce or absent in later-erupted units, providing evidence for eruption of a second, more primitive basalt that was of insufficient volume to skew whole-rock mixing trends. Nucleation delay models suggest that the absence of overgrowth rims or quench crystals in these glassy basaltic selvages reflect residence times of a few hours at rhyolitic temperatures before eruption. Short basalt-rhyolite mixing timescales reflect rapid destabilization of the magmatic system and triggering of the eruption by mafic recharge. The ascent of both primitive and evolved basaltic magmas from depth mirrors events in recent volcano-tectonic episodes in the north of Iceland, suggesting that mafic recharge was driven by a plate boundary rifting event
Tuning porosity of coal-derived activated carbons for CO2 adsorption
No full textA simple method was developed to tune the porosity of coal-derived activated carbons (ACs), which provided a model adsorbent system to investigate the volumetric CO2 adsorption performance. Specifically, the method involved the variation of the activation temperature in a K2CO3 induced chemical activation process which could yield ACs with defined microporous (<2 nm, including ultra-microporous <1 nm) and meso-micro-porous structures. CO2 adsorption isotherms revealed that the microporous AC has the highest measured CO2 adsorption capacity (6.0 mmol·g–1 at 0 °C and 4.1 mmol·g–1 at 25 °C), whilst ultra-microporous AC with a high packing density exhibited the highest normalized capacity with respect to packing volume (1.8 mmol·cm−3 at 0 °C and 1.3 mmol·cm–3 at 25 °C), which is significant. Both experimental correlation analysis and molecular dynamics simulation demonstrated that (i) volumetric CO2 adsorption capacity is directly proportional to the ultra-micropore volume, and (ii) an increase in micropore sizes is beneficial to improve the volumetric capacity, but may lead a low CO2 adsorption density and thus low pore space utilization efficiency. The adsorption experiments on the ACs established the criterion for designing CO2 adsorbents with high volumetric adsorption capacity.Keywords coal-derived activated carbons, porosity, CO2 adsorption, molecular dynamics<br/
Impact of myocardial fibrosis on cardiovascular structure, function and functional status in heart failure with preserved ejection fraction
No full textMyocardial fibrosis, measured using cardiovascular magnetic resonance extracellular volume (ECV), is associated with adverse outcome in heart failure with preserved ejection fraction but the mechanisms by which myocardial fibrosis exerts this deleterious effect are unclear. We performed mediation analyses of data from the PIROUETTE (The Pirfenidone in Patients with Heart Failure and Preserved Left Ventricular Ejection Fraction) trial to determine whether myocardial fibrotic regression causes changes in cardiovascular function and functional status following antifibrotic therapy. Regression of myocardial fibrosis correlated with improvements in 6-minute walk test and KCCQ clinical summary score. The only outcome variable that demonstrated a treatment effect was an increase in left ventricular ejection fraction (LVEF). The estimated average causal mediation effects of myocardial ECV, absolute myocardial extracellular matrix volume and absolute myocardial cellular volume on LVEF were 6.1%, 21.5%, and 13.7% respectively, none of which were significant and therefore not mediated by myocardial fibrosis. (PIROUETTE; NCT02932566)
Cascade adsorptive separation of light hydrocarbons by commercial zeolites
No full textAdsorptive separation of light hydrocarbons by porous solids provides an energy-efficient alternative to state-of-the-art cryogenic distillation. However, an optimal balance between the cost, performance and stability of the sorbent material is yet to be achieved for industrial applications. Here, we report the efficient separation of C2 and C3 hydrocarbons by a faujasite zeolite (Na-X, Si/Al=1.23). A tandem configuration of two fixed-beds packed with Na-X affords complete dynamic separation of the ternary mixture of C2H2/C2H4/C2H6 (1/49.5/49.5; v/v/v) under ambient conditions. Pressure-swing desorption on the latter fixed-bed gives ethylene (>99.50%, 1.80 mmol g-1) and ethane (>99.99%, 1.41 mmol g-1). In situ synchrotron X-ray powder diffraction revealed the binding sites for C2H2 and C2H4 in Na-X. This study highlights the potential application of commercial zeolites for challenging industrial separations
Energy Efficiency Optimization for PSOAM Mode-Groups based MIMO-NOMA Systems
No full textPlane spiral orbital angular momentum (PSOAM) mode-groups (MGs) and multiple-input multiple-output nonorthogonal multiple access (MIMO-NOMA) serve as two emerging techniques for achieving high spectral efficiency (SE) in the next-generation networks. In this paper, a PSOAM MGs based multi-user MIMO-NOMA system is studied, where the base station transmits data to users by utilizing the generated PSOAM beams. For such scenario, the interference between users in different PSOAM mode groups can be avoided, which leads to a significant performance enhancement. We aim to maximize the energy efficiency (EE) of the system subject to the constraints of the total transmission power and the minimum data rate. This designed optimization problem is non-convex owing to the interference among users, and hence is quite difficult to tackle directly. To solve this issue, we develop a dual layer resource allocation algorithm where the bisection method is exploited in the outer layer to obtain the optimal EE and a resource distributed iterative algorithm is exploited in the inner layer to optimize the transmit power. Besides, an alternative resource allocation algorithm with Deep Belief Networks (DBN) is proposed to cope with the requirement for low computational complexity. Simulation results verify the theoretical findings and demonstrate the proposed algorithms on the PSOAM MGs based MIMO-NOMA system can obtain a better performance comparing to the conventional MIMO-NOMA system in terms of EE