Abstract. While social networks can provide an ideal platform for upto-date information from individuals across the world, it has also proved to be a place where rumours fester and accidental or deliberate misinformation often emerges. In this article, we aim to support the task of making sense from social media data, and specifically, seek to build an autonomous message-classifier that filters relevant and trustworthy information from Twitter. For our work, we collected about 100 million public tweets, including users' past tweets, from which we identified 72 rumours (41 true, 31 false). We considered over 80 trustworthiness measures including the authors' profile and past behaviour, the social network connections (graphs), and the content of tweets themselves. We ran modern machine-learning classifiers over those measures to produce trustworthiness scores at various time windows from the outbreak of the rumour. Such time-windows were key as they allowed useful insight into the progression of the rumours. From our findings, we identified that our model was significantly more accurate than similar studies in the literature. We also identified critical attributes of the data that give rise to the trustworthiness scores assigned. Finally we developed a software demonstration that provides a visual user interface to allow the user to examine the analysis.

[Structure: see text] Two approaches to the synthesis of (2S,4S)-5,5-dichloroleucine are compared, and the parent amino acid was used in the first total synthesis of the polychlorinated marine natural product, dysamide B. A key step was the lead tetraacetate-mediated decarboxylation of an alpha,alpha-dichloro acid in the presence of 1,4-cyclohexadiene to generate the dichloromethyl group.

[Structure: see text] The total synthesis of the marine metabolite clavosolide A is reported which confirms the structure and absolute configuration of the natural product as the symmetrical diolide glycosylated by permethylated D-xylose moieties, 2.

The first syntheses of two natural products, catechols 1 and 2, isolated from Plectranthus sylvestris (labiatae), are reported. Oxygen-18 labeling studies support the proposed intermediacy of a stabilized benzylic cation in the acid-promoted cyclization of an aldehyde and benzylic homoallylic alcohol possessing an electron-rich aromatic ring. In contrast, with an electron-deficient aromatic ring the pathway via a benzylic cation is only minor. [reaction: see text]

Guided by Honig and Hatch's conceptualization of bridging and buffering, we analyzed the first teacher collective bargaining agreements negotiated after the enactment of the Ohio Teacher Evaluation System to understand how state law has shaped provisions for teacher evaluation, compensation, reductions in force (RIF), transfers, and contract renewal. We found surprising variation in provisions across districts. Most notable was how districts defined comparable evaluations in making RIF decisions. Bridging districts provided the greatest protections for the most accomplished teachers, regardless of seniority. In contrast, buffering districts have RIF provisions based on seniority.

In the garden pea (Pisum sativum L.), the mutant allele le blocks the conversion of GAZ0 to GAl (Ingram et al., 1984), reducing the endogenous level of GAl (Ross et al., 1992; Smith et al., 1992). This is responsible for the dwarf phenotype of le plants. It has been suggested that le codes for an altered form of GA20 3B-hydroxylase, the enzyme that catalyzes the step GAZo to GAl (Ross et al., 1989; MacMillan, 1990). Recently, however, Smith (1992) questioned this proposa1 in a model addressing severa1 important aspects of GA biosynthesis in pea. According to this model the apical bud itself does not metabolize GAZo to a significant extent. Instead, it is suggested that GAl production is confined largely to young stem tissue, where it is regulated by an inhibitor of GA2o 30-hydroxylation produced by the apical bud (and possibly by young, expanding leaflets). Smith (1992) proposed that in le plants the inhibitor is constitutively produced, thereby blocking GA1 production. Smiths model is based on the metabolism of [13C,3H]GAz0 by excised leaves, stems, and apical buds. The metabolites were chromatographed by HPLC as the free acids (Smith, 1992). In extracts from apical buds and leaves the level of radioactivity co-eluting with GAl (GA1-like) was very low. This level was higher in extracts from stems, but in a11 cases was not affected by the Le/le gene difference.We have investigated the metabolism of [13C,3H]GAz0 in plants either left intact or with their apical buds removed (decapitated). Furthermore, we have reproduced the experimental conditions used by Smith (1992) and have analyzed the resulting extracts by HPLC as the free acids and methyl esters, and by GC-MS. Our results do not support the in- MATERIALS A N D METHODSThe lines used were the isolines 205+ (Le, tall) and 205-(le, dwarf), developed from cross L2 X L77 at Hobart (Tasmania, Australia). The plants were grown, two per pot, in a heated glasshouse under an 18-h photoperiod (Reid and Potts, 1986). Experiments were conducted when the plants had expanded to five to seven leaves (including the scale leaves).The substrate in a11 experiments was [17-13C,3H~]GA~~ (1.27 X 10" Bq mmol-'; Ingram et al., 1984). Two experimental systems were used. First, substrate (2 r g in 10 PL of ethanol) was applied to the second uppermost fully expanded leaf of 12 tall and 12 dwarf plants. Immediately afterward, six tall and six dwarf plants were decapitated by excising just below the node situated three nodes up from the treated leaf. This left three intemodes and two leaves above the treated leaf in decapitated plants. After 2 d, the uppermost two of these intemodes were harvested together (stem portion), as were the stipules, petiole, and leaflets of the uppermost leaf (leaf portion). Intact plants were harvested by first excising the apical portion as before and then harvesting the next two intemodes down and (separately) the associated leaf, as for decapitated plants. A11 excised portions were then immersed in cold (-20°C) methanol.Second, the technique of Smith ...

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Guided by Honig and Hatch's (2004) conceptualization of bridging and buffering, we undertook an analysis of reduction in force (RIF) provisions from 546 Ohio teacher collective bargaining agreements. We asked the following question: Are the most disadvantaged school districts providing greater protections to tenured teachers when making RIF decisions? Logistic regression analysis revealed a negative relationship ( p < 0.05) between the percentage of students within the district living in poverty and bridging to state efforts to reform the use of seniority alone in RIF decisions.