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  1. Free, publicly-accessible full text available November 9, 2022
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  4. Although graph convolutional networks (GCNs) that extend the convolution operation from images to graphs have led to competitive performance, the existing GCNs are still difficult to handle a variety of applications, especially cheminformatics problems. Recently multiple GCNs are applied to chemical compound structures which are represented by the hydrogen-depleted molecular graphs of different size. GCNs built for a binary adjacency matrix that reflects the connectivity among nodes in a graph do not account for the edge consistency in multiple molecular graphs, that is, chemical bonds (edges) in different molecular graphs can be similar due to the similar enthalpy and interatomicmore »distance. In this paper, we propose a variant of GCN where a molecular graph is first decomposed into multiple views of the graph, each comprising a specific type of edges. In each view, an edge consistency constraint is enforced so that similar edges in different graphs can receive similar attention weights when passing information. Similarly to prior work, we prove that in each layer, our method corresponds to a spectral filter derived by the first order Chebyshev approximation of graph Laplacian. Extensive experiments demonstrate the substantial advantages of the proposed technique in quantitative structure-activity relationship prediction.« less
    Free, publicly-accessible full text available July 20, 2022
  5. Free, publicly-accessible full text available November 1, 2022
  6. There has been an explosion of ideas in soft robotics over the past decade, resulting in unprecedented opportunities for end effector design. Soft robot hands offer benefits of low-cost, compliance, and customized design, with the promise of dexterity and robustness. The space of opportunities is vast and exciting. However, new tools are needed to understand the capabilities of such manipulators and to facilitate manipulation planning with soft manipulators that exhibit free-form deformations. To address this challenge, we introduce a sampling based approach to discover and model continuous families of manipulations for soft robot hands. We give an overview of themore »soft foam robots in production in our lab and describe novel algorithms developed to characterize manipulation families for such robots. Our approach consists of sampling a space of manipulation actions, constructing Gaussian Mixture Model representations covering successful regions, and refining the results to create continuous successful regions representing the manipulation family. The space of manipulation actions is very high dimensional; we consider models with and without dimensionality reduction and provide a rigorous approach to compare models across different dimensions by comparing coverage of an unbiased test dataset in the full dimensional parameter space. Results show that some dimensionality reduction is typically useful in populating the models, but without our technique, the amount of dimensionality reduction to use is difficult to predict ahead of time and can depend on the hand and task. The models we produce can be used to plan and carry out successful, robust manipulation actions and to compare competing robot hand designs.« less
  7. Abstract Spin-valley locking in monolayer transition metal dichalcogenides has attracted enormous interest, since it offers potential for valleytronic and optoelectronic applications. Such an exotic electronic state has sparsely been seen in bulk materials. Here, we report spin-valley locking in a Dirac semimetal BaMnSb 2 . This is revealed by comprehensive studies using first principles calculations, tight-binding and effective model analyses, angle-resolved photoemission spectroscopy measurements. Moreover, this material also exhibits a stacked quantum Hall effect (QHE). The spin-valley degeneracy extracted from the QHE is close to 2. This result, together with the Landau level spin splitting, further confirms the spin-valley lockingmore »picture. In the extreme quantum limit, we also observed a plateau in the z -axis resistance, suggestive of a two-dimensional chiral surface state present in the quantum Hall state. These findings establish BaMnSb 2 as a rare platform for exploring coupled spin and valley physics in bulk single crystals and accessing 3D interacting topological states.« less
    Free, publicly-accessible full text available December 1, 2022
  8. ABSTRACT The feedback from young stars (i.e. pre-supernova) is thought to play a crucial role in molecular cloud destruction. In this paper, we assess the feedback mechanisms acting within a sample of 5810 H ii regions identified from the PHANGS-MUSE survey of 19 nearby (<20 Mpc) star-forming, main-sequence spiral galaxies [log(M⋆/M⊙) = 9.4–11]. These optical spectroscopic maps are essential to constrain the physical properties of the H ii regions, which we use to investigate their internal pressure terms. We estimate the photoionized gas (Ptherm), direct radiation (Prad), and mechanical wind pressure (Pwind), which we compare to the confining pressure of their host environmentmore »(Pde). The H ii regions remain unresolved within our ∼50–100 pc resolution observations, so we place upper (Pmax) and lower (Pmin) limits on each of the pressures by using a minimum (i.e. clumpy structure) and maximum (i.e. smooth structure) size, respectively. We find that the Pmax measurements are broadly similar, and for Pmin the Ptherm is mildly dominant. We find that the majority of H ii regions are overpressured, Ptot/Pde = (Ptherm + Pwind + Prad)/Pde > 1, and expanding, yet there is a small sample of compact H ii regions with Ptot,max/Pde < 1 (∼1 per cent of the sample). These mostly reside in galaxy centres (Rgal < 1 kpc), or, specifically, environments of high gas surface density; log(Σgas/M⊙ pc−2) ∼ 2.5 (measured on kpc-scales). Lastly, we compare to a sample of literature measurements for Ptherm and Prad to investigate how dominant pressure term transitions over around 5 dex in spatial dynamic range and 10 dex in pressure.« less
    Free, publicly-accessible full text available October 28, 2022