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An LLL algorithm with symmetries
No full textWe give a generalization of the Lenstra–Lenstra–Lovász (LLL) lattice-reduction algorithm that is valid for an arbitrary (split, semisimple) reductive group [Formula: see text]. This can be regarded as “lattice reduction with symmetries.” We make this algorithm explicit for the classical groups [Formula: see text], [Formula: see text], and for the exceptional group [Formula: see text]
The Michael Mason Prize: Development and feasibility testing of a complex intervention to improve adherence to fracture prevention medicine.
Full text linkOBJECTIVES: Only 12% of people recommended fracture prevention medicines remain on treatment 1 year post fracture. The improving uptake of Fracture Prevention treatments (iFraP) intervention aims to improve shared decision-making (SDM) about, and uptake of, osteoporosis medicines in Fracture Liaison Services (FLS). This paper details development and feasibility. METHODS: Intervention development was underpinned by (1) theories of SDM, medicines adherence, and behaviour change; (2) integrated findings from seven development studies; and (3) extensive patient and clinician contribution, identifying key 'needs' to address and the intervention's content, functionality and scope.Feasibility testing was conducted at one English FLS. Intervention consultations were observed and audio recorded. Interviews completed with FLS clinicians and patients explored perceived acceptability and feasibility. RESULTS: Intervention development identified patient and clinician unmet needs for personalised and evidence-based information about osteoporosis, its consequences, and its treatment within and after FLS consultations, to facilitate clinical and SDM about medicines. The prototype intervention (osteoporosis decision support tool, clinician skills training, and information resources), was designed to meet identified needs and overcome barriers to use.Clinicians delivered the prototype iFraP intervention in 10 consultations with consenting patients. Findings demonstrated that the intervention was acceptable and feasible to deliver, with potential to improve patient outcomes. The intervention was refined to support implementation. CONCLUSION: The multi-facilitated approach to intervention development and testing ensured that the iFraP intervention appears acceptable and feasible for use in UK FLS to support SDM about osteoporosis medicines. The iFraP trial will evaluate implementation, and cost and clinical effectiveness
Scaling W State Circuits in the qudit Clifford Hierarchy
Full text linkWe identify a novel qudit gate which we refer to as the gate. This is an alternate generalization of the qutrit T gate to any odd prime dimension d, in the dth level of the Clifford hierarchy. Using this gate which is efficiently realizable fault-tolerantly should a certain conjecture hold, we deterministically construct in the Clifford+ gate set, d-qubit W states in the qudit {|0⟩, |1⟩} subspace. For qutrits, we show deterministic and fault-tolerant constructions for the three-qubit W state with T count three, for the six-qubit W state, and for any power-of-three-qubit W state. Furthermore, we adapt these constructions to recursively scale the W state size to arbitrary size N, in O(N) gate count and O(log N) depth. This is moreover deterministic for any size qubit W state, and for any prime d-dimensional qudit W state, size a power of d. For these purposes, we devise constructions of the |0⟩ -controlled Pauli X gate and the controlled Hadamard gate in any prime qudit dimension. These decompositions, for which exact synthesis is unknown in Clifford+T for d > 3, may be of independent interest
Fenscapes: archaeology, natural heritage and environmental change in the Fens of eastern England
Full text linkEnhancing power density and cycle life of NMC811 battery cathodes via combined dense calendering and laser patterning.
Full text linkThe charging time of Li-ion batteries is an important bottleneck in the wider adoption of electric vehicles (EVs). A common strategy to improve the rate performance is improving ion transport by patterning the electrode. However, these patterning methods usually increase the electrode porosity, thereby decreasing the volumetric energy density. In this work, we leverage the ability of Single Crystal LiNi0.8Mn0.1Co0.1O2 (SC-NMC811) electrodes to be calendered to higher packing densities than traditional cathodes, which then allows to offset additional porosity introduced by electrode patterning. We calendar SC-NMC811 electrodes to a 25% porosity and then introduce hole patterns spaced 100 to 600 µm apart using laser processing with a goal to maintain average porosities below 30%. As expected, we found systematic improvements in the rate performance with increasing hole density and used operando charge photometry to explore the limits of mass transport in the regions surrounding the holes but interestingly, we also observe improved capacity retention when using patterned electrodes. We found that there is less cathode lattice oxygen loss when using patterned cathodes, this in turn reduces transition metal shuttling reduces anode solid electrolyte interphase (SEI) impedance growth. We demonstrated a reduction in oxygen loss by both electron energy loss spectroscopy (EELS) mapping, X-ray diffraction (XRD) mapping and X-ray diffraction computed tomography (XRD-CT). Overall, SC-NMC811 electrode's ability to withstand over-calendering offers the opportunity to introduce laser patterned holes while maintaining the average porosity below 30%. This increases both the rate performance and longevity of the electrodes
Augmenting military decision making with artificial intelligence
Full text linkAbstract As artificial intelligence (AI) plays an increasing role in operations on battlefields, we should consider how it might also be used in the strategic decisions that happen before a military operation even occurs. One such critical decision that nations must make is whether to use armed force. There is often only a small group of political and military leaders involved in this decision-making process. Top military commanders typically play an important role in these deliberations around whether to use force. These commanders are relied upon for their expertise. They provide information and guidance about the military options available and the potential outcomes of those actions. This article asks two questions: (1) how do military commanders make these judgements? and (2) how might AI be used to assist them in their critical decision-making processes? To address the first, I draw on existing literature from psychology, philosophy, and military organizations themselves. To address the second, I explore how AI might augment the judgment and reasoning of commanders deliberating over the use of force. While there is already a robust body of work exploring the risks of using AI-driven decision-support systems, this article focuses on the opportunities, while keeping those risks firmly in view
Kimonos, Ponchos and Blue Jeans: The Politics of Clothing in Alberto Fujimori’s Performative Populism
Full text linkThis article explores the role of clothing in populism through an analysis of Alberto Fujimori, Peru’s one-time autocrat (1990–2000). Drawing on the discursive-performative approach to populism and novel primary sources, this article makes the process-traced argument fashion may be essential to the performance of populism since, from the perspective of populist leaders, clothing is capable of overcoming some limitations of discourse. Despite several rhetorical shortcomings, clothing allowed Fujimori to perform ‘the popular’. Through kimonos, Fujimori differentiated himself from Peru’s White elite, through ponchos he built identification with indigenous Peruvians and through blue jeans he embodied a hands-on governing style. Clothing allowed Fujimori to build charismatic authority without rhetorical skill, transmitted nuanced messages alongside discourse and convinced many Peruvians of the authenticity of his populist project. This analysis of Fujimori highlights the oft-neglected importance of clothing in politics while providing a methodological blueprint for scholars interested in addressing this important gap
A new look at the jet-storm track relationship in the North Pacific and North Atlantic
Full text linkAbstract. The western ocean boundaries of the North Pacific (NP) and North Atlantic (NA) set favourable conditions for upper-level jets and baroclinic weather systems that propagate downstream and form the storm tracks. Despite these similarities between the two ocean basins, distinct forcing mechanisms during the winter season give rise to differences in the jet intensity, structure, and variability, as well as in the storm track activity. In particular, the phenomenon of the NP midwinter suppression of the monthly averaged storm track activity sparked ongoing discussions about fundamental differences between jet-storm track interactions in the NP and NA. This study introduces an alternative method, which avoids monthly averaging, to study the relationship between the background jet core strength (U) and, as a measure of storm track activity, the eddy kinetic energy (EKE), both evaluated in the upper troposphere. With our approach, we find that the U-EKE relationship is remarkably consistent across the NP and NA, with previously observed differences largely attributable to the differing timescales of jet variability in the two basins. For our interpretation, the separate consideration of two distinct timescales is important: On seasonal timescales, baroclinic instability results in an increase of EKE with increasing U from summer to winter. In contrast, on sub-monthly timescales, particularly during winter, EKE decreases with increasing U, reflecting the effect of baroclinic conversion. Periods of enhanced baroclinic conversion lead to reduced baroclinicity (quantified by U) and high EKE, whereas periods of low baroclinic conversion are followed by high U and low EKE. In this framework, the NP midwinter suppression of monthly averaged EKE reflects that, in midwinter, U remains persistently high in the NP (because baroclinic conversion is suppressed) while EKE is reduced. In other words, in the NP, jet strength varies predominantly from month to month, whereas in the NA, it varies more within individual months such that the midwinter suppression of the monthly averaged storm track activity is less obvious in the NA. The observed U-EKE relationship implies that the jet core strength U alone cannot explain the EKE variability across seasons, and we reveal the additional importance of the jet width, which affects eddy characteristics. A reduced jet width likely plays a role in deforming and meridionally confining eddies, thereby reducing their baroclinic growth. For jets with comparable weak to moderate core strengths in summer and winter, the summertime jets tend to be narrower with smaller EKE. Similarly, very strong jets in winter are particularly narrow, which implies reduced EKE, supporting the observed U-EKE relationship in winter. Finally, cyclone composites show that the reduced EKE during strong jet episodes in winter is manifested by a reduction in the amplitude of the cyclones' surface pressure anomalies, and, in particular of their associated troughs and ridges. Therefore, the reduction of EKE with increasing U is not related to a decrease in cyclone frequency, but rather to a reduction in cyclone intensity and the associated upper-level wave pattern
Benchmark of cellular deconvolution methods using a multi-assay dataset from postmortem human prefrontal cortex.
Full text linkCellular deconvolution of bulk RNA-sequencing data using single cell/nuclei RNA-seq reference data is an important strategy for estimating cell type composition in heterogeneous tissues, such as the human brain. Here, we generate a multi-assay dataset in postmortem human dorsolateral prefrontal cortex from 22 tissue blocks, including bulk RNA-seq, reference snRNA-seq, and orthogonal measurement of cell type proportions with RNAScope/ImmunoFluorescence. We use this dataset to evaluate six deconvolution algorithms. Bisque and hspe were the most accurate methods. The dataset, as well as the Mean Ratio gene marker finding method, is made available in the DeconvoBuddies R/Bioconductor package
The viscoelastic rheology of transient diffusion creep
Full text linkAbstract Polycrystalline materials have a viscoelastic rheology where the strains produced by stresses depend on the timescale of deformation. Energy can be stored elastically within grain interiors and dissipated by a variety of different mechanisms. One such dissipation mechanism is diffusionally accommodated/assisted grain boundary sliding, also known as transient diffusion creep. Here we detail a simple reference model of transient diffusion creep, based on finite element calculations with simple grain shapes: a regular hexagon in two dimensions and a tetrakaidecadedron in three dimensions. The linear viscoelastic behaviour of the finite element models can be well-described by a parameterized extended Burgers model, which behaves as a Maxwell model at low frequencies and as an Andrade model at high frequencies. The parametrization has a specific relaxation strength, Andrade exponent and Andrade time. The Andrade exponent depends only on the angles at which grains meet at triple junctions, and can be related to the exponents of stress singularities that occur at triple junctions in purely elastic models without diffusion. A comparison with laboratory experiments shows that the simple models here provide a lower bound on the observed attenuation. However, there are also clearly additional dissipative processes occurring in laboratory experiments that are not described by these simple models