Palaeozoic giant dragonfies were hawker predators

The largest insects to have ever lived were the giant meganeurids of the Late Palaeozoic, ancient stem relatives of our modern dragonfies. With wingspans up to 71cm, these iconic insects have been the subject of varied documentaries on Palaeozoic life, depicting them as patrolling for prey through coal swamp forests amid giant lycopsids, and cordaites. Such reconstructions are speculative as few defnitive details of giant dragonfy biology are known. Most specimens of giant dragonfies are known from wings or isolated elements, but Meganeurites gracilipes preserves critical body structures, most notably those of the head. Here we show that it is unlikely it thrived in densely forested environments where its elongate wings would have become easily damaged. Instead, the species lived in more open habitats and possessed greatly enlarged compound eyes. These were dorsally hypertrophied, a specialization for long-distance vision above the animal in fight, a trait convergent with modern hawker dragonfies. Sturdy mandibles with acute teeth, strong spines on tibiae and tarsi, and a pronounced thoracic skewness are identical to those specializations used by dragonfies in capturing prey while in fight. The Palaeozoic Odonatoptera thus exhibited considerable morphological specializations associated with behaviours attributable to ‘hawkers’ or ‘perchers’ among extant Odonata.This work benefted from a grant of the French ‘Agence Nationale de la Recherche’ via the program ‘Investissements d’avenir’ (ANR-11-INBS-0004-RECOLNAT)JP and MP gratefully acknowledge research support from the Grant Agency of the Czech Republic No. 18-03118 SThe work of MSE was supported by US National Science Foundation grant DEB-114416

Health Indicators of Native Hawaiian and Pacific Islanders in the United States

This study aimed to describe health indicators and behaviors of Native Hawaiian and Pacific Islander (NHPI) adults and to compare findings to previous reports on US NHPI and the US population. A sample of N = 100 (56 M, 44 F) NHPI adults aged 40–59 years completed an anonymous questionnaire addressing education and household income, tobacco use, physical activity, fruit and vegetable (F&V) consumption, cancer screening and health status. Objective measures of height and weight were taken to calculate body mass index (BMI). The study sample consisted of 49% current smokers and the majority was not meeting guidelines for physical activity (80%) or F&V consumption (99%). Cancer screening rates ranged from 0 to 57% and were higher among females. Mean BMI was 33.9 ± 7.5 kg/m2 and 95% were overweight or obese. While 36.7% were hypertensive, only 11.1% were taking prescribed medication. Compared to both the general US population and available data for US NHPI, study participants reported higher prevalence of obesity and chronic conditions (hypertension, high cholesterol, diabetes, and angina/CHD) and lower levels of physical activity, F&V consumption and cancer screening rates. Study findings contribute to the limited knowledge regarding health behaviors of US NHPI. Comparisons to US data increase evidence of NHPI health disparities, while comparisons to previous NHPI studies emphasize the magnitude of unhealthy lifestyle behaviors and subsequent adverse health conditions for this particular sample. Further improvements to community outreach and recruitment strategies could successfully encourage high-risk individuals to participate in health promotion and behavior intervention studies to improve NHPI health behaviors

Vinyl cation formation by decomposition of vinyllead(IV) triacetates. Part 2

The products resulting from the reductive elimination of lead(II) acetate from four E- and Z-pairs of vinyllead triacetates have been examined for evidence that these highly unstable lead compounds are a potential source of vinyl cations, including the less stable primary vinyl cations. The vinyllead triacetates which incorporated either methoxy or phenyl groups for intramolecular cation trapping, were generated by reaction of the corresponding tributyl(vinyl)stannanes with lead tetraacetate. In four cases participation by methoxy and phenyl groups occurred to produce cyclic compounds, strongly implicating vinyl cation formation

Electrophilic vinylations by vinyllead triacetates and tribenzoates generated by tin–lead exchange

Trimethyl(vinyl)stannanes undergo a rapid tin-lead exchange with lead tetraacetate to give high yields of unstable vinyllead triacetates. Solutions of vinyllead triacetates produced in this way react with soft carbon nucleophiles such as β-dicarbonyl compounds and nitronate salts to give moderate to good yields of C-vinylated products. The method is more economical in terms of vinyl group incorporation than previously reported vinylations by vinyllead triacetates. An even faster tin-lead exchange has been observed when trimethyl(vinyl)stannanes are treated with lead tetrabenzoate, and vinylations with this reagent proceeded in significantly higher yields