Faster Cut Sparsification of Weighted Graphs.

A cut sparsifier is a reweighted subgraph that maintains the weights of the cuts of the original graph up to a multiplicative factor of ( 1 ± ϵ ) . This paper considers computing cut sparsifiers of weighted graphs of size O ( n log ( n ) / ϵ 2 ) . Our algorithm computes such a sparsifier in time O ( m · min ( α ( n ) log ( m / n ) , log ( n ) ) ) , both for graphs with polynomially bounded and unbounded integer weights, where α ( · ) is the functional inverse of Ackermann's function. This improves upon the state of the art by Benczúr and Karger (SICOMP, 2015), which takes O ( m log 2 ( n ) ) time. For unbounded weights, this directly gives the best known result for cut sparsification. Together with preprocessing by an algorithm of Fung et al. (SICOMP, 2019), this also gives the best known result for polynomially-weighted graphs. Consequently, this implies the fastest approximate min-cut algorithm, both for graphs with polynomial and unbounded weights. In particular, we show that it is possible to adapt the state of the art algorithm of Fung et al. for unweighted graphs to weighted graphs, by letting the partial maximum spanning forest (MSF) packing take the place of the Nagamochi-Ibaraki forest packing. MSF packings have previously been used by Abraham et al. (FOCS, 2016) in the dynamic setting, and are defined as follows: an M-partial MSF packing of G is a set F = { F 1 , … , F M } , where F i is a maximum spanning forest in G \ ⋃ j = 1 i - 1 F j . Our method for computing (a sufficient estimation of) the MSF packing is the bottleneck in the running time of our sparsification algorithm.

Hope as a predictor for COVID-19 vaccine uptake in the US: a cross-sectional survey of 11,955 adults.

Widespread vaccine uptake is critical for ending the COVID-19 pandemic. As public health officials focus on overcoming vaccine hesitancy, simultaneously boosting hope may be equally important in the US. We analyzed data from an online cross-sectional survey conducted in June 2021. Participants were 11,955 US adults (ages 18-83) of various ethnicities, living in urban and rural settings. Of these, 71.3% had some college education. Mean age was 32.3 years and 72.4% reported being vaccinated against COVID-19. Main measures were COVID-19 self-reported vaccination status (vaccine uptake), vaccine hesitancy (Adult Vaccine Hesitancy Scale), and hope (Adult Hope Scale). The US grand mean hope score fell within the low-hope range. COVID-19 vaccine uptake was positively associated with hope, even after adjusting for vaccine hesitancy, gender, age, ethnicity, income, and urban vs. rural residence. The strong relationship between hope, vaccine confidence and vaccine uptake persisted across US populations at risk for low vaccine uptake. Our mediation analysis revealed that, for every unit increase in hope, the probability of being vaccinated went up by 5% points. Of this association, 52% was not mediated by vaccine hesitancy, but rather through a direct pathway from hope to vaccine uptake. Mediation analyses of US populations at risk of low vaccine uptake revealed similar findings. Hope may play an important role in vaccine uptake by reducing vaccine hesitancy and by directly enhancing vaccine uptake. Especially in populations at risk of low vaccine uptake, vaccine interventions that boost hope may augment public health efforts to increase US vaccination rates.

Animated, video entertainment-education to improve vaccine confidence globally during the COVID-19 pandemic: an online randomized controlled experiment with 24,000 participants.

BACKGROUND: Science-driven storytelling and entertainment-education (E-E) media demonstrate potential for promoting improved attitudes and behavioral intent towards health-related practices. Months after the outbreak of coronavirus disease 2019 (COVID-19), emerging research highlights the essential role of interventions to improve public confidence in the COVID-19 vaccine. To improve vaccine confidence, we designed three short, animated videos employing three research-informed pedagogical strategies. These can be distributed globally through social media platforms, because of their wordless and culturally accessible design. However, the effectiveness of short, animated storytelling videos, deploying various pedagogic strategies, needs to be explored across different global regions. METHODS/DESIGN: The present study is a multi-site, parallel group, randomized controlled trial (RCT) comparing the effectiveness of (i) a storytelling-instructional-humor approach, (ii) a storytelling-analogy approach, (iii) a storytelling-emotion-focused approach, and (iv) no video. For our primary outcomes, we will measure vaccine hesitancy, and for secondary outcomes, we will measure behavioral intent to seek vaccination and hope. Using online platforms, we will recruit 12,000 participants (aged 18-59 years) from the USA and China, respectively, yielding a total sample size of 24,000. DISCUSSION: This trial uses innovative online technology, reliable randomization algorithms, validated survey instruments, and list experiments to establish the effectiveness of three short, animated videos employing various research-informed pedagogical strategies. Results will be used to scientifically support the broader distribution of these short, animated video as well as informing the design of future videos for rapid, global public health communication. TRIAL REGISTRATION: German Clinical Trials Register DRKS #00023650 . Date of registration: 2021/02/09.

Anthracene-Based Receptors with a Turn-on Fluorescence Response for Nitrate.

Herein we describe the design, synthesis, and anion binding properties of bicyclic receptors with two or three anthracenes, which show a turn-on fluorescence response in the presence of nitrate and chaotropic anions in a buffered aqueous solution. The receptor with two anthracenes binds nitrate with 103 M-1 affinity and stabilizes it in the inner cavity though electrostatic, hydrogen bonding, and anion-π interactions.

Crystal structure of 1-iodo-3-{[4-(tert-butyl-sulfan-yl)phen-yl]ethyn-yl}azulene.

The title compound, C20H19IS, features a 1,3-disubstituted azulene involving an ethynylene elongated 4-(tert-butyl-sulfanyl)-phenyl sidearm and an iodine atom as the substituents. The azulene ring system is almost planar (r.m.s. deviation = 0.012 Å) and subtends a dihedral angle of 35.7 (1)° with the benzene ring. As a result of the inherent dipole character of the azulene core, a supra-molecular π-π dimer [separation between the centroids of the five- and seven-membered rings = 3.7632 (10) Å] with anti-parallel orientated mol-ecules can be observed in the crystal. The packing is consolidated by an unusual I⋯π(acetyl-ene) contact [I⋯Cg = 3.34 Å, C-I⋯Cg = 173.3°], and a very weak C-H⋯π inter-action is also found in the structure, with the azulene five-membered ring as the acceptor.

Crystal structure of diethyl 2-amino-6-[(thio-phen-3-yl)ethyn-yl]azulene-1,3-di-carboxyl-ate.

The title compound, C22H19NO4S, has an almost planar geometry supported by intra-molecular N-H⋯O and C-H⋯O hydrogen bonds. The thio-phene ring is inclined to the azulene ring by 4.85 (16)°, while the eth-oxy-carbonyl groups are inclined to the azulene ring by 7.0 (2) and 5.7 (2)°. In the crystal, mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(12) ring motif. The dimers are linked via C-H⋯π inter-actions, forming sheets parallel to (10-1).

Crystal structure of 1,3-bis-{[4-(acetyl-sulfanyl)phenyl]ethynyl}azulene.

In the title compound, C30H20O2S2, the dihedral angles between the central azulene ring system (r.m.s. deviation = 0.039 Å) and the pendant benzene rings are 28.96 (7) and 55.15 (7)°. The dihedral angles between the benzene rings and their attached acetyl-sulfanyl groups are 59.60 (10) and 84.79 (10)°. The expected π-π stacking inter-actions are not observed in the crystal structure; instead, the packing features C-H⋯O hydrogen bonds, which link the mol-ecules into C(12) [010] chains, which are supported by weak C-H⋯π contacts.

Copy number variation of chromosome 5A and its association with Q gene expression, morphological aberrations, and agronomic performance of winter wheat cultivars.

KEY MESSAGE: Our investigations combine chromosome 5A copy number variation associated with relative 5A Q gene expression and morphological and agronomic data to characterize the occurrence of speltoid plants in winter wheat cultivars. The occurrence of speltoid aberrants in wheat breeding is a serious problem that may result in rejection of a candidate cultivar during licensing. The spear-shaped, hard threshing spike is caused by copy number reduction of the domestication gene Q, located on the long arm of wheat chromosome 5A. As a member of the APETALA2-like transcription factor family, the 5AQ gene is involved in flower development and pleiotropically controls other agronomic traits. In this report, a characterization of instability of chromosome 5A is given and effects due to the loss of the Q gene and other genes are discussed. Based on pyrosequencing, we correctly predicted the 5AQ copy number for 392 of 402 tested offspring plants (97.5 %) originating from single speltoid plants of eleven wheat cultivars. The findings indicate that the resulting speltoid plants were either reduced in chromosome 5A copy number or possessed a partial deletion of the distal end of chromosome arm 5AL. 5AQ specific real-time PCR analysis revealed varying transcription levels among cultivars. During early spike development, the relative transcription of the 5AQ gene was always lower in speltoids than in normal square headed wheat plants, most likely leading to the occurrence of the characteristic speltoid spike phenotype. The parallel analysis of 18 agronomic traits revealed pleiotropic effects governed by genes located on 5A. Our results demonstrate that through pyrosequencing one can identify aneuploidy or deletions within chromosome 5A to select against the occurrence of speltoid plants in wheat seedlings.

1,3-Diiodo-azulene-2-carbonitrile.

In the title compound, C11H5I2N, the two iodine-atom substitutents with their large atomic sizes lead to short intra-molecular I⋯H distances (3.01 Å). In the crystal, the tris-ubstituted azulene system forms π-stacks [centroid-centroid distance = 3.6343 (11) Å] along the a-axis direction, showing the characteristic azulene inter-action mode between the electron-rich five-membered ring and the electron-deficient seven-membered ring. I⋯I [3.9129 (2) Å] non-covalent contacts are observed along with weak C-H⋯N and C-H⋯π. bonds.

Syntheses of the hexahydroindene cores of indanomycin and stawamycin by combinations of iridium-catalyzed asymmetric allylic alkylations and intramolecular Diels-Alder reactions.

Short and concise syntheses of the hexahydroindene cores of the antibiotics indanomycin (X-14547 A) and stawamycin are presented. Key methods used are an asymmetric iridium-catalyzed allylic alkylation, a modified Julia olefination, a Suzuki-Miyaura coupling, and an intramolecular Diels-Alder reaction.

1,4-Bis[4-(tert-butyl-sulfan-yl)phen-yl]buta-1,3-diyne.

The asymmetric unit of the title compound, C(24)H(26)S(2), consits of one half-mol-ecule, which is located on a center of inversion. The two benzene rings are exactly coplanar while the tert-butyl group is oriented nearly perpendicular to the ring plane [C-S-C-C = -81.14 (11)°].

2,2,2-Trifluoro-1-[3-(2,2,2-trifluoro-acet-yl)azulen-1-yl]ethanone.

There are two mol-ecules in the asymmetric unit of the title compound, C(14)H(6)F(6)O(2), in which the azulene systems possess an almost planar geometry with maximum deviations of 0.0438 (15) and 0.0396 (14) Å. Besides intra- and inter-molecular C-H⋯O and C-H⋯F inter-actions, the structure displays three F⋯F contacts [2.793 (2), 2.8820 (17) and 2.9181 (16) Å]. Furthermore, a characteristic azulene π-stacking is observed with an alternating sequence of electron-rich five-membered rings and electron-deficient seven-membered rings [centroid-centroid distances = 3.5413 (12), 3.6847 (12), 3.5790 (12) and 3.7718 (12) Å].

Differential effects of the brefeldin A analogue (6R)-hydroxy-BFA in tobacco and Arabidopsis.

The effects of two brefeldin A (BFA) analogues (BFA lactam; 6(R)-hydroxy-BFA) on plant cells were tested. Although these two compounds elicited BFA-like effects in mammalian cells, the lactam analogue failed to elicit a response in plant cells. By contrast, while the 6(R)-hydroxy-BFA analogue gave rise to a classic BFA response in tobacco mesophyll protoplasts and true leaves of Arabidopsis (redistribution of Golgi enzymes into the ER), it failed to cause the formation of BFA-compartments in Arabidopsis root cells and cotyledonary leaves. Even when the GNL1-LM mutant of Arabidopsis, which has a cis-Golgi located BFA-sensitive ARF-GEF, was used, the 6(R)-hydroxy analogue failed to elicit a response at conventional BFA concentrations. Only at concentrations of over 200 µM did 6(R)-hydroxy-BFA elicit a BFA-like effect. These differences are interpreted in terms of the different properties of the respective TGN- (Arabidopsis roots) and cis-Golgi- (tobacco mesophyll) localized BFA-sensitive ARF-GEFs.

Tuning of inter- versus intrachain magnetic interactions in cyano-bridged Ni(II)/M(III) (M = Cr, Fe, Co) chain complexes.

The reaction of [M(CN)6]3- (M = Cr3+, Fe3+, Co3+) with the nickel(II) complex of 2,4-diamino-1,3,5-triazin-6-yl-{3-(1,3,5,8,12-pentaazacyclotetradecane)} ([NiL]2+) in excess of ANO3 or ACl (A = Li+, Na+, K+, Rb+, Cs+, NH4+) leads to the cyano-bridged dinuclear assemblies A{[NiL][M(CN)6]}.xH2O (x = 2-5). X-ray structures of Li{[NiL][Cr(CN)6]}.5H2O, NH4{[NiL][Cr(CN)6]}.3.5H2O, K{[NiL][Cr(CN)6]}.4H2O, K{[NiL][Fe(CN)6]}.4H2O, Rb{[NiL][Fe(CN)6]}.3.5H2O, and Cs{[NiL][Fe(CN)6]}.3.5H2O, as well as the powder diffractometry of the entire Fe(III) series, are reported. The magnetic properties of the assemblies are dependent on the monocation A and discussed in detail. New efficient pathways for ferromagnetic exchange between Ni(II) and Fe(III) or Cr(III) are demonstrated. Field dependencies of the magnetization for the Fe(III) samples at low temperature and low magnetic field indicate a weak interchain antiferromagnetic coupling, which is switched to ferromagnetic coupling at increasing magnetic field (metamagnetic behavior). The interchain magnetic coupling can be tuned by the size of the A cations.