trans-3,3′,4,5′-Tetra­meth­oxy­stilbene

The title compound, C18H20O4, was synthesized by a Wittig–Horner reaction of diethyl 3,4-dimeth­oxy­benzyl­phosphate and 3,5-dimeth­oxy­benzaldehyde. In the crystal, the dihedral angle between the two aromatic rings is 2.47 (12)°. All the meth­oxy groups are almost coplanar with the aromatic ring to which they are attached [C—C—O—C torsion angles = −2.8 (3), −5.2 (4), −176.3 (2) and −178.0 (2)°]

Towards Robust Aspect-based Sentiment Analysis through Non-counterfactual Augmentations

While state-of-the-art NLP models have demonstrated excellent performance for aspect based sentiment analysis (ABSA), substantial evidence has been presented on their lack of robustness. This is especially manifested as significant degradation in performance when faced with out-of-distribution data. Recent solutions that rely on counterfactually augmented datasets show promising results, but they are inherently limited because of the lack of access to explicit causal structure. In this paper, we present an alternative approach that relies on non-counterfactual data augmentation. Our proposal instead relies on using noisy, cost-efficient data augmentations that preserve semantics associated with the target aspect. Our approach then relies on modelling invariances between different versions of the data to improve robustness. A comprehensive suite of experiments shows that our proposal significantly improves upon strong pre-trained baselines on both standard and robustness-specific datasets. Our approach further establishes a new state-of-the-art on the ABSA robustness benchmark and transfers well across domains.Comment: 10pages,1 figure,10 table

2,3-Diamino­phenazine tetra­hydrate

The title compound, C12H10N4·4H2O, was obtained from a room-temperature solution of o-phenyl­enediamine and copper acetate. In the crystal structure, there are significant π–π stacking inter­actions, with a centroid–centroid separation of 3.575 (2) Å. In addition, inter­molecular O—H⋯O, N—H⋯O, N—H⋯N and O—H⋯N hydrogen bonds link 2,3-diamino­phenazine mol­ecules and water mol­ecules, forming a three-dimensional framework

Fragmentation function of g→QQˉ(3S1[8])g\to Q\bar{Q}(^3S_1^{[8]}) in soft gluon factorization and threshold resummation

We study the fragmentation function of the gluon to color-octet $^3S_1$ heavy quark-antiquark pair using the soft gluon factorization (SGF) approach, which expresses the fragmentation function in a form of perturbative short-distance hard part convoluted with one-dimensional color-octet $^3S_1$ soft gluon distribution (SGD). The short distance hard part is calculated to next-to-leading order in $\alpha_s$ and a renormalization group equation for the SGD is derived. By solving the renormalization group equation, threshold logarithms are resummed to all orders in perturbation theory. The comparison with gluon fragmentation function calculated in NRQCD factorization approach indicates that the SGF formula resums a series of velocity corrections in NRQCD which are important for phenomenological study.Comment: 38 pages, 8 figure