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External and internal sources of cognitive group awareness information: Effects on perception and usage
Get PDFGroup selection or group formation is an important but difficult task in learning groups. Group awareness tools collect, transform, and present group awareness information to provide learners, but also teachers with relevant information e.g., about potential learning partners. For these educational tools, the value and usage of the provided information may depend on how it is gathered and where it ultimately comes from. In our study (N = 150), we thus investigate how information from different sources is perceived and ranked. In the study, information about the skills of an anonymous person in a profile was either provided by external sources (teacher assessment, knowledge test result) or internal sources (self-assessment). Results show that information from external sources is perceived as more credible and weighted higher than internal self-assessed information. No difference between information from external personal teacher assessments and external non-personal knowledge tests was found. Hence, it is worth exploring possible effects of other external ratings than teacher assessments to see if these insights are transferable to other contexts
Effect of Linaclotide on Colonic Motility Assessed With Intraluminal Colonic High-Resolution Manometry in Healthy Subjects. An Acute, Open Label, Randomized, Crossover, Reader-Blinded Study
Get PDFBackground: Polyethilenglicole (PEG), bisacodyl, prucalopride, and linaclotide were demonstrated to be superior to placebo for the treatment of chronic constipation. In a recent study, we reported the actions of PEG, bisacodyl, and prucalopride on colonic motor patterns. The aim of the present study was to evaluate the effect of linaclotide as compared to placebo on colonic motility assessed with high-resolution manometry (HRM). Methods: In 10 volunteers (30.3 ± 10.6 years), two colonic HRM studies (40 solid-state sensors, 2.5 cm spaced) were performed at least 10 days apart. After 90 min of basal recording, linaclotide 290 μg or placebo was administered orally in double-blind, randomized, cross-over fashion, and the recording continued for 180 min before and after a standardized meal. Colonic motility index (MI) of the right, left colon, and rectum, expressed as a ratio of the baseline value, was compared between treatments by means of a mixed model analysis. The number of high-amplitude propagated sequences, of long-distance propagating sequences, and of pan-colonic pressurizations was compared between treatments. Results: Linaclotide induced more long-distance propagating sequences than placebo (34.9 ± 41.2 vs. 3.0 ± 5.2, p = 0.026), especially during the meal and post-meal phases of the recording. The total number of pancolonic pressurizations did not differ between treatments. However, a significant increase in the mean number of pre-prandial pancolonic pressurizations was observed following linaclotide administration (p = 0.043). No treatment effect was found on the change in colonic MI from the baseline in any region of the colon. Conclusions: In healthy controls, acute administration of linaclotide increases the total number of long-distance propagating sequences and the pre-prandial pancolonic pressurizations
Comprehensive characterisation of lignin-based bio-bitumen as a sustainable paving material
Get PDFRising demand, increasing prices, and growing environmental concerns necessitate the exploration of sustainable alternatives in transportation infrastructure. Lignin has shown promise as a partial substitute for petroleum-derived bitumen, but its efficacy needs to be comprehensively assessed. This study investigates the effects of incorporating two types of lignin at dosages of 3 % and 5 %. Thermogravimetric analyser, Fourier-transform infrared spectroscopy, X-ray diffraction, and dynamic shear rheometer were employed to characterise physicochemical properties of lignin and the corresponding modified bitumen. Considering the decomposition of lignin, the mixing temperatures should below 180 °C. The addition of lignin reduced ageing susceptibility, implying lignin may serve both as a partial bitumen replacement and antioxidant. Rheological tests showed minor improvements in rutting resistance and reduced stiffness-controlled critical temperatures, while creep rate-controlled temperatures remained largely unchanged. However, these changes were not statistically significant. Thus, partially replacing petroleum bitumen with bio-sourced lignin is a technically viable and sustainable solution
Reporting innovations in pharmacology and drug development, upholding excellence and improving author experience at the British Journal of Pharmacology in 2024
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A Comparison of Stoichiometric and Lean Burn Ammonia-Hydrogen Co- Fuelling in a Modern Spark Ignition Engine
Get PDFAmmonia (NH3) is emerging as a promising fuel for longer range decarbonised heavy transport, predominantly due to relative favourable characteristics as an effective hydrogen carrier. This is despite generally unfavourable combustion and toxicity attributes, restricting ammonia's end use to applications where robust health and safety protocols can always be assured. In the currently reported work, a spark ignited thermodynamic single cylinder research engine was equipped with separate gaseous ammonia and hydrogen port injection fuelling, with the aim of understanding the impact of varied co-fuelling upon combustion, fuel economy and engine-out emissions (and the arising implications upon future emissions after-treatment). Under stoichiometric conditions, the engine could be operated in a stable manner on pure NH3 at low-to-medium speeds and medium-to-high engine loads, with up to ~20% hydrogen (by energy) required at the lowest engine loads. Engine-out NH3 emissions remained relatively high across the stoichiometric operating map (ranging between 7000-8000ppm), with engine out NOx remaining comparatively low (between 1000-2000ppm). An alternative lean burn operating strategy was then investigated, with the intent of balancing ammonia slip versus NOx to a degree facilitating minimised tailpipe emissions by future use of Selective Catalytic Reduction (SCR) emissions after-treatment technology, where the NH3 slip can be directly utilised as NOx reductant (i.e. eliminating the need for a urea storage and injection system found in conventional SCR systems). Ideally such SCR systems operate with a fixed "alpha ratio" equal to ~1 (where this ratio is the ratio of engine-out NH3 to NOx on a ppm basis, with a value of unity indicating the ideal amount of reductant to simultaneously consume NH3 slip and decompose NOx). This was achieved by conducting a series of parametric sweeps, varying the air-to-fuel ratio and hydrogen content in the fuel mix to evaluate the ideal combinations of hydrogen substitution ratio and relative air-to-fuel ratio (λ) to achieve an alpha ratio of 1. It was concluded that operating the engine with ~20% hydrogen and slightly lean (λ~1.2) would result in an ideal alpha ratio of ~1 across most of the operating map, with little variation in alpha ratio or lambda noted with changing engine load. The results indicate, apparently for the first time, the high promise of a lean burn spark ignition ammonia/hydrogen co-fuelling strategy for balancing engine-out NOx and NH3 emissions via SCR after-treatment. The supplementary hydrogen along with the lean operation was noted to also result in small improvements in indicated thermal efficiency of 1-2% compared to baseline stoichiometric operation with minimum hydrogen
Guest Editorial: Special Cluster on Emerging Beam Steering Technologies of Antenna Systems for Millimeter-Wave and Beyond Communications
No full textSpace-time correlations in monitored kinetically constrained discrete-time quantum dynamics
Get PDFState-of-the-art quantum simulators permit local temporal control of interactions and midcircuit readout. These capabilities open the way towards the exploration of intriguing nonequilibrium phenomena. We illustrate this with a kinetically constrained many-body quantum system that has a natural implementation on Rydberg quantum simulators. The evolution proceeds in discrete time and is generated by repeatedly entangling the system with an auxiliary environment that is monitored and reset after each time-step. Despite featuring an uncorrelated infinite-temperature average stationary state, the dynamics displays coexistence of fast and slow space-time regions in stochastic realizations of the system state. The time-record of measurement outcomes on the environment serves as natural probe for such dynamical heterogeneity, which we characterize using tools from large deviation theory. Our work establishes the large deviation framework for discrete-time open quantum many-body systems as a means to characterize complex dynamics and collective phenomena in quantum processors and simulators. Introduction.-Statistical mechanics is typically concerned with the analysis of equilibrium and nonequi-librium stationary properties of physical systems [1-3]. Certain many-body systems may however be characterized by "seemingly trivial", i.e., orderless stationary states while displaying intricate collective dynamical behavior [4-10]. Kinetically constrained models provide a paradigmatic example of such interesting (typically slow) dynamics towards structureless thermodynamic equilibrium states [11, 12]. These many-body systems are described by simple dynamical rules that only allow for transitions between single-particle states if a given condition , e.g., the absence or presence of particles in their close neighborhood, is satisfied. This reduction in the connectivity between configurations of the system can result in highly correlated and heterogeneous dynamics [13-19]. Within the framework of classical stochastic systems , methods from large deviation theory have been employed to investigate collective dynamical behavior in kinetically constrained models, leading, for instance, to new insights into the glass transition [20-29]. Extending these models to the quantum realm holds the promise to reveal new dynamical behavior and nonequilibrium phases [19, 30-36]. Interestingly, this undertaking also constitutes a daunting task, in particular due to the intrinsic complexity of many-body quantum systems. Currently available quantum simulation platforms are promising candidates to address this open challenge [37-44]. Improvements in both the fidelity and the versatility of implementable quantum operations already allowed for a deeper understanding of quantum many-body dynamics [45-59]. Most notably, in-circuit me
Regression graphs and sparsity-inducing reparametrizations
Get PDFThat parametrization and sparsity are inherently linked raises the possibility that relevant models, not obviously sparse in their natural formulation, exhibit a population-level sparsity after reparametrization. In covariance models, positive-definiteness enforces additional constraints on how sparsity can legitimately manifest. It is therefore natural to consider reparametrization maps in which sparsity respects positive definiteness. The paper provides insight into structures on the physically-natural scale that induce and are induced by sparsity after reparametrization. Of the four structures initially uncovered, the richest can be generated, under a causal ordering, by the joint-response graphs studied by Wermuth & Cox (2004). This connection leads to an interpretation of approximate zeros and explains modelling implications of enforcing sparsity after reparameterization: in effect, the relation between two variables would be declared null if relatively direct regression effects were negligible and other effects manifested through long paths. The Iwasawa decomposition of the general linear group, combined with the graphical-models interpretation, points to a class of reparametrizations for the chain-graph models (Andersson et al., 2001), with undirected and directed acyclic graphs as special cases. The insights have a bearing on methodology, some aspects of which are developed. An extensive simulation uses the theoretical insights to further explore regimes under which reparametrization is beneficial
Uses of Gas Sorption and Mercury Porosimetry Methods in Studies of Heritage Materials
Get PDFThis review explains why pore structure characterisation, particularly utilising gas sorption and mercury porosimetry, is important for the study of many different types of heritage materials, such as for determining their raw materials, methods of fabrication, and ancient uses. It then describes the basic experimental methods, including details of particular relevance to heritage materials. Several relatively novel methods, such as gas over-condensation, scanning curves and loops, and hybrid experiments, not often used with heritage materials, are also described and their potential applications discussed. In particular, gas over-condensation can probe pores of sizes from the molecular scale to hundreds of microns in one experiment, and thus can be used to provide “fingerprints” characteristic of the internal void space of different types of ceramics or glasses to aid in identification without damaging the finds. This work also surveys the various applications of gas sorption and mercury porosimetry to ancient ceramics, glasses, and building materials, with particular discussion of uses in testing the mode of action and effectiveness of various conservation methods
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