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A new method for the detection of gas-phase hydroperoxides is described. The clustering chemistry of CF3O- is exploited to produce speciated measurements of several hydroperoxides with high sensitivity and fast time response. Correspondence of airborne observations made with this technique and the established HPLC method is illustrated. CF3O- appears to be(More)
Isoprene is a significant source of atmospheric organic aerosol; however, the oxidation pathways that lead to secondary organic aerosol (SOA) have remained elusive. Here, we identify the role of two key reactive intermediates, epoxydiols of isoprene (IEPOX = beta-IEPOX + delta-IEPOX) and methacryloylperoxynitrate (MPAN), which are formed during isoprene(More)
Secondary organic aerosol (SOA) formation from the photooxidation of one monoterpene (α-pinene) and two sesquiterpenes (longifolene and aromadendrene) is investigated in the Caltech environmental chambers. The effect of NOx on SOA formation for these biogenic hydrocarbons is evaluated by performing photooxidation experiments under varying NOx conditions.(More)
2-Methyl-3-buten-2-ol (MBO) is an important biogenic hydrocarbon emitted in large quantities by pine forests. Atmospheric photooxidation of MBO is known to lead to oxygenated compounds, such as glycolaldehyde, which is the precursor to glyoxal. Recent studies have shown that the reactive uptake of glyoxal onto aqueous particles can lead to formation of(More)
The large number, definition, varied application and validity of named Australian biogeographical regions reflect their ad hoc development via disparate methods or case study idiosyncracies. They do not represent a coherent system. In order to resolve these uncertainties an Australian Bioregionalisation Atlas is proposed as a provisional hierarchical(More)
We present a statistical representation of the aggregate effects of deep convection on the chemistry and dynamics of the upper troposphere (UT) based on direct aircraft observations of the chemical composition of the UT over the eastern United States and Canada during summer. These measurements provide unique observational constraints on the chemistry(More)
We previously found that 201TI SPECT is a highly specific agent for detection of metabolic activity of childhood brain tumors. To compare the relative diagnostic accuracy of 201TI and a technetium-based tumor-avid agent, we have obtained SPECT in 19 children using 201TI (37-111 MBq) followed immediately by 99mTc-methoxyisobutylisonitrile (MIBI) (370-740(More)
We study the problem of applying adaptive filters for approximate query processing in a distributed stream environment. We propose filter bound assignment protocols with the objective of reducing communication cost. Most previous works focus on value-based queries (e.g., average) with numerical error tolerance. In this paper, we cover entity-based queries(More)
Peroxy radical reactions (RO2 + RO2) from the NO3-initiated oxidation of isoprene are studied with both gas chromatography and a chemical ionization mass spectrometry technique that allows for more specific speciation of products than in previous studies of this system. We find high nitrate yields (∼ 80 %), consistent with other studies. We further see(More)
STUDY DESIGN Controlled laboratory study. OBJECTIVES To measure the architectural properties of rat supraspinatus muscle after a complete detachment of its distal tendon. METHODS Supraspinatus muscles were released from the left humerus of 29 Sprague-Dawley rats (mass, 400-450 g), and the animals were returned to cage activity for 2 weeks (n=12), 4(More)