Single particle characterization using the soot particle aerosol mass spectrometer (SP-AMS)

Understanding the impact of atmospheric black carbon (BC) containing particles on human health and radiative forcing requires knowledge of the mixing state of BC, including the characteristics of the materials with which it is internally mixed. In this study, we demonstrate for the first time the capabilities of the Aerodyne Soot-Particle Aerosol Mass Spectrometer equipped with a light scattering module (LS-SP-AMS) to examine the mixing state of refractory BC (rBC) and other aerosol components in an urban environment (downtown Toronto). K-means clustering analysis was used to classify single particle mass spectra into chemically distinct groups. One resultant cluster is dominated by rBC mass spectral signals (C+1 to C+5) while the organic signals fall into a few major clusters, identified as hydrocarbon-like organic aerosol (HOA), oxygenated organic aerosol (OOA), and cooking emission organic aerosol (COA). A nearly external mixing is observed with small BC particles only thinly coated by HOA ( 28% by mass on average), while over 90% of the HOA-rich particles did not contain detectable amounts of rBC. Most of the particles classified into other inorganic and organic clusters were not significantly associated with BC. The single particle results also suggest that HOA and COA emitted from anthropogenic sources were likely major contributors to organic-rich particles with low to mid-range aerodynamic diameter (dva). The similar temporal profiles and mass spectral features of the organic clusters and the factors from a positive matrix factorization (PMF) analysis of the ensemble aerosol dataset validate the conventional interpretation of the PMF results.

James Fitzpiers Fitzgerald, Captain Thomas Lee, and the problem of ‘secret traitors’: conflicted loyalties during the Nine Years’ War, 1594-1603

Existing evidence pertaining to Ireland’s Nine Years’ War (1594–1603) strongly lends itself to the impression that the majority of Old English Palesmen, at least those of higher social status, chose to support the English crown during this conflict rather than their co-religionist Gaelic Irish countrymen. Loyalties, however, were anything but straightforward and could depend on any number of cultural values, social concerns, and economic incentives. Nevertheless, James Fitzpiers Fitzgerald, a ‘Bastard Geraldine’ who served as sheriff of Kildare, seemed to have been driven by a genuine sense of duty to the English crown and establishment. With the outbreak of hostilities in the 1590s, Fitzpiers proved to be a devout crown servitor, risking life and limb to confront the English queen’s Irish enemies. But, in late 1598 he suddenly, and somewhat inexplicably, threw his lot in with the Irish confederacy, defying the government he had once championed. During the ensuing investigation, the Dublin administration accumulated much damning evidence against Fitzpiers, including a patriotic plea from rebel leader Hugh O’Neill which urged Fitzpiers to defend his Irish homeland from the oppressions of English Protestant rule. Yet, at the very same time, a counter case was made by Fitzpiers’s controversial English friend, Captain Thomas Lee, which argued that Fitzpiers’s actions were more loyal than anyone could have imagined. Through an examination of Fitzpiers’s perplexing case, this paper will explore the complicated nature of allegiances in 1590s Ireland and how loyalties were not always what they seemed.

Jessica Lee talking to Everglades angler David Rose

http://digitalcommons.fiu.edu/fce_lter_photos/1294/thumbnail.jpg

Global distributions of diazotrophs abundance and biomass - Depth integrated values computed from a collection of source datasets - Contribution to the MAREDAT World Ocean Atlas of Plankton Functional Types

The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedented global data set for ecological and biochemical analysis and modeling as well as a clear mandate for compiling additional existing data and for focusing future data gathering efforts on key groups in key areas of the ocean. The present data set presents depth integrated values of diazotrophs abundance and biomass, computed from a collection of source data sets.