A two-step approach to achieve secondary amide transamidation enabled by nickel catalysis.

A long-standing challenge in synthetic chemistry is the development of the transamidation reaction. This process, which involves the conversion of one amide to another, is typically plagued by unfavourable kinetic and thermodynamic factors. Although some advances have been made with regard to the transamidation of primary amide substrates, secondary amide transamidation has remained elusive. Here we present a simple two-step approach that allows for the elusive overall transformation to take place using non-precious metal catalysis. The methodology proceeds under exceptionally mild reaction conditions and is tolerant of amino-acid-derived nucleophiles. In addition to overcoming the classic problem of secondary amide transamidation, our studies expand the growing repertoire of new transformations mediated by base metal catalysis

Most Admired Leader/Most Admired Follower

In introducing concepts of leadership and followership to students, this experiential exercise highlights qualities associated with the leader and follower roles. Various learning objectives guide the development of the exercise. They focus on identification of behavioral qualities possessed by both leaders and followers and on the importance of the leader-follower relationship to the organization’s achievement of goals. Theoretical underpinnings are stressed throughout. In the exercise, students individually develop a list of characteristics associated with their own most admired leader or follower and then share their lists in small groups. In plenary discussion, groups share all characteristics identified, and the instructor leads discussion to achieve stated learning objectives. Exercise handouts, instructions for facilitating classroom discussion, and a summary of theories that may be used as a postexercise student handout are provided

Environmental attributes influencing the distribution of Burkholderia pseudomallei in Northern Australia

Factors responsible for the spatial and temporal clustering of Burkholderia pseudomallei in the environment remain to be elucidated. Whilst laboratory based experiments have been performed to analyse survival of the organism in various soil types, such approaches are strongly influenced by alterations to the soil micro ecology during soil sanitisation and translocation. During the monsoonal season in Townsville, Australia, B. pseudomallei is discharged from Castle Hill (an area with a very high soil prevalence of the organism) by groundwater seeps and is washed through a nearby area where intensive sampling in the dry season has been unable to detect the organism. We undertook environmental sampling and soil and plant characterisation in both areas to ascertain physiochemical and macro-floral differences between the two sites that may affect the prevalence of B. pseudomallei. In contrast to previous studies, the presence of B. pseudomallei was correlated with a low gravimetric water content and low nutrient availability (nitrogen and sulphur) and higher exchangeable potassium in soils favouring recovery. Relatively low levels of copper, iron and zinc favoured survival. The prevalence of the organism was found to be highest under the grasses Aristida sp. and Heteropogon contortus and to a lesser extent under Melinis repens. The findings of this study indicate that a greater variety of factors influence the endemicity of melioidosis than has previously been reported, and suggest that biogeographical boundaries to the organisms' distribution involve complex interactions

Listening to the Voices of Community Health Workers: A Multilevel, Culture-Centered Approach to Overcoming Structural Barriers in U.S. Latinx Communities

Community Health Workers (CHWs) are often incorporated into efforts to reduce health disparities for vulnerable populations. However, their voices are rarely the focus of research when considering how to increase their job effectiveness and sustainability. The current study addresses this gap by privileging the voices of 28 CHWs who work with Latinx communities in Nebraska through in-depth, semi-structured interviews. Using a multilevel, Culture-Centered Approach (CCA) to Health Communication, we identified two key structural communication issues: (a) increasing language accommodation and (b) increasing (and stabilizing) network integration across three ecological levels of health behavior (individual, microsystem, and exosystem). This study shows the uniquely valuable perspective that CHWs have as they navigate hierarchical health care structures and community cultures to meet the needs of their Latinx clients. Findings suggest that CHWs should be included in health care organization and policy discussions to reduce health disparities for Latinx populations

Book Reviews

Book reviews of: Bound in Wedlock: Slave and Free Black Marriage in the Nineteenth Century. By Tera W. Hunter. (Cambridge: The Belknap Press of Harvard University Press, 2017. 404 pp. $29.95, cloth. ISBN: 9780674045712.) Delta Epiphany: Robert F. Kennedy in Mississippi. By Ellen B. Meacham. (Jackson: University Press of Mississippi, 2018. Acknowledgements, source notes, bibliography, about the photographers, index, Pp. xi, 293.$28 cloth. ISBN 9781496817457.) Let the People See: The Story of Emmett Till. By Elliott J. Gorn. (New York: Oxford University Press, 2018. Acknowledgements, source notes, bibliography, index, Pp. xi, 400. $27.95 hardcover. ISBN: 9780199335122.) The Ordeal of the Reunion: A New History of Reconstruction. By Mark Wahlgren Summers. (Chapel Hill: The University of North Carolina Press, 2014. 528 pp., 21 halftones, notes, bibl., index.$40.00 cloth. ISBN: 978-1-4696-1757-2.) Stepdaughters of History: Southern Women and the American Civil War. By Catherine Clinton. (Baton Rouge: Louisiana State University Press, 2016. $48.00 hardback. ISBN: 978807164570.) Frontiers of Science: Imperialism and Natural Knowledge in the Gulf South Borderlands, 1500- 1850. By Cameron B. Strang. (Chapel Hill, NC: University of North Carolina Press, 2018. Acknowledgements, illustrations, index. Pp. vii, 357.$39.95 Cloth. ISBN: 9781469640471.) Vicksburg, Grant’s Campaign that Broke the Confederacy. By Donald L. Miller. (New York: Simon & Schuster, 2019. Notes, illustrations, index. Pp. 663. $35.00.

Turbulent Mixing in the Surface Layers of Accreting Neutron Stars

During accretion a neutron star (NS) is spun up as angular momentum is transported through its surface layers. We study the resulting differentially rotating profile, focusing on the impact this has for type I X-ray bursts. The predominant viscosity is likely provided by the Tayler-Spruit dynamo. The radial and azimuthal magnetic field components have strengths of ~10^5 G and ~10^10 G, respectively. This leads to nearly uniform rotation at the depths of interest for X-ray bursts. A remaining small shear transmits the accreted angular momentum inward to the NS interior. Though this shear gives little viscous heating, it can trigger turbulent mixing. Detailed simulations will be required to fully understand the consequences of mixing, but our models illustrate some general features. Mixing has the greatest impact when the buoyancy at the compositional discontinuity between accreted matter and ashes is overcome. This occurs at high accretion rates, at low spin frequencies, or may depend on the ashes from the previous burst. We then find two new regimes of burning. The first is ignition in a layer containing a mixture of heavier elements from the ashes. If ignition occurs at the base of the mixed layer, recurrence times as short as ~5-30 minutes are possible. This may explain the short recurrence time of some bursts, but incomplete burning is still needed to explain these bursts' energetics. When mixing is sufficiently strong, a second regime is found where accreted helium mixes deep enough to burn stably, quenching X-ray bursts. We speculate that the observed change in X-ray burst properties near one-tenth the Eddington accretion rate is from this mechanism. The carbon-rich material produced by stable helium burning would be important for triggering and fueling superbursts. (abridged)Comment: Accepted for publication in The Astrophysical Journal, 16 pages, 15 figure

Increasing biomass in Amazonian forest plots

A previous study by Phillips et al. of changes in the biomass of permanent sample plots in Amazonian forests was used to infer the presence of a regional carbon sink. However, these results generated a vigorous debate about sampling and methodological issues. Therefore we present a new analysis of biomass change in old-growth Amazonian forest plots using updated inventory data. We find that across 59 sites, the above-ground dry biomass in trees that are more than 10 cm in diameter (AGB) has increased since plot establishment by 1.22 ± 0.43 Mg per hectare per year (ha-1 yr-1), where 1 ha = 104 m2), or 0.98 ± 0.38 Mg ha-1 yr-1 if individual plot values are weighted by the number of hectare years of monitoring. This significant increase is neither confounded by spatial or temporal variation in wood specific gravity, nor dependent on the allometric equation used to estimate AGB. The conclusion is also robust to uncertainty about diameter measurements for problematic trees: for 34 plots in western Amazon forests a significant increase in AGB is found even with a conservative assumption of zero growth for all trees where diameter measurements were made using optical methods and/or growth rates needed to be estimated following fieldwork. Overall, our results suggest a slightly greater rate of net stand-level change than was reported by Phillips et al. Considering the spatial and temporal scale of sampling and associated studies showing increases in forest growth and stem turnover, the results presented here suggest that the total biomass of these plots has on average increased and that there has been a regional-scale carbon sink in old-growth Amazonian forests during the previous two decades