Oceans cover over two-thirds of the Earth's surface, and the particles emitted to the atmosphere by waves breaking on sea surfaces provide an important contribution to the planetary albedo. During ...the International Chemistry Experiment in the Arctic LOwer Troposphere (ICEALOT) cruise on the R/V Knorr in March and April of 2008, organic mass accounted for 15-47% of the submicron particle mass in the air masses sampled over the North Atlantic and Arctic Oceans. A majority of this organic component (0.1 - 0.4 μ m⁻³) consisted of organic hydroxyl (including polyol and other alcohol) groups characteristic of saccharides, similar to biogenic carbohydrates found in seawater. The large fraction of organic hydroxyl groups measured during ICEALOT in submicron atmospheric aerosol exceeded those measured in most previous campaigns but were similar to particles in marine air masses in the open ocean (Southeast Pacific Ocean) and coastal sites at northern Alaska (Barrow) and northeastern North America (Appledore Island and Chebogue Point). The ocean-derived organic hydroxyl mass concentration during ICEALOT correlated strongly to submicron Na concentration and wind speed. The observed submicron particle ratios of marine organic mass to Na were enriched by factors of ~10²-~10³ over reported sea surface organic to Na ratios, suggesting that the surface-controlled process of film bursting is influenced by the dissolved organic components present in the sea surface microlayer. Both marine organic components and Na increased with increasing number mean diameter of the accumulation mode, suggesting a possible link between organic components in the ocean surface and aerosol-cloud interactions.
Measurements of total peroxy radicals (HO
2
+ RO
2
) and nitrate radical (NO
3
) were made on the NOAA research vessel R/V
Brown
along the U.S. Gulf Coast during the TexAQS 2006 field campaign. The ...measurements were modelled using a constrained box-model based upon the Master Chemical Mechanism (MCM). The agreement between modelled and measured HO
2
+ RO
2
was typically within ∼40% and, in the unpolluted regions, within 30%. The analysis of the model results suggests that the MCM might underestimate the concentrations of some acyl peroxy radicals and other small peroxy radicals. The model underestimated the measurements of NO
3
by 60–70%, possibly because of rapid heterogeneous uptake of N
2
O
5
. The MCM model results were used to estimate the composition of the peroxy radical pool and to quantify the role of DMS, isoprene and alkenes in the formation of RO
2
in the different regions. The measurements of HO
2
+ RO
2
and NO
3
were also used to calculate the gas-phase budget of NO
3
and quantify the importance of organic peroxy radicals as NO
3
sinks. RO
2
accounted, on average, for 12–28% of the total gas-phase NO
3
losses in the unpolluted regions and for 1–2% of the total gas-phase NO
3
losses in the polluted regions.
A current question in theories of visual cognition is whether distinct cognitive processes subserve perceptual judgments and perception for action. This paper examines bisection tasks which have ...previously been used to demonstrate a dissociation between perception and action in brain injured patients. Forty neurologically intact participants completed a standard line bisection task and a variant of this task--rod bisection. A typical leftwards bias was observed for line bisection but when asked to locate the centre of wooden rods using perceptual judgments, a distinct rightwards bias was shown. By contrast, when participants were asked to pick the rods up by the centre, their judgments showed no bias. The results are in line with theories suggesting that perception and action are independent; however, alternative explanations are also considered.
OBJECTIVES:To investigate differences in management and outcomes for patients admitted to the hospital with TIA according to care on a stroke unit (SU) or alternate ward setting up to 180 days post ...event.
METHODS:TIA admissions from 40 hospitals participating in the Australian Stroke Clinical Registry during 2010–2013 were assessed. Propensity score matching was used to assess outcomes by treatment group including Cox proportional hazards regression to compare survival differences and other appropriate multivariable regression models for outcomes including health-related quality of life and readmissions.
RESULTS:Among 3,007 patients with TIA (mean age 73 years, 54% male), 1,110 pairs could be matched. Compared to management elsewhere in hospitals, management in an SU was associated with improved cumulative survival at 180 days post event (hazard ratio 0.57, 95% confidence interval 0.35–0.94; p = 0.029), despite not being statistically significant at 90 days (hazard ratio 0.66, 95% confidence interval 0.33–1.31; p = 0.237). Overall, there were no differences for being discharged on antihypertensive medication or with a care plan, and the 90- to 180-day self-reported outcomes between these groups were similar. In subgroup analyses of 461 matched pairs treated in hospitals in one Australian state (Queensland), patients treated in an SU were more often prescribed aspirin within 48 hours (73% vs 62%, p < 0.001) and discharged on antithrombotic medications (84% vs 71%, p < 0.001) than those not treated in an SU.
CONCLUSIONS:Hospitalized patients with TIA managed in SUs had better survival at 180 days than those treated in alternate wards, potentially through better management, but further research is needed.
Aerosol chemical, physical, and optical measurements were made aboard the NOAA R/V Ronald H. Brown off the coast of New England from July 12 through August 10, 2002, as part of the New England Air ...Quality Study (NEAQS). Measurements (generally 20 to 100 km from the coast) were made downwind of urban centers (New York City, Boston) and rural areas, and in air masses that had not been in contact with land for several days. On average during NEAQS, 75 ± 8% of the sub‐10 μm aerodynamic diameter dry aerosol mass sampled 18 m above the sea surface was in the sub‐1 μm fraction (size cut at 55% RH). The major submicrometer aerosol components were ammonium sulfate and particulate organic matter (POM, defined here as 1.6 times the mass concentration of organic carbon) comprising more than 92 ± 4% of the total mass. Under northwesterly flow with an average submicrometer total mass concentrations of 11 ± 4.5 μg m−3, POM was the dominant component (68 ± 8%) followed by (NH4)xHySO4 (23 ± 8%), inorganic oxidized material (IOM) (6 ± 4%), and EC (3 ± 1%). Under southwesterly flow with an average submicrometer total mass concentrations of 30 ± 11 μg m−3, (NH4)xHySO4 was the dominant component (54 ± 9%) followed by POM (41 ± 9%), IOM (3 ± 2%), and EC (2 ± 1%). Mie calculations using submicrometer nonrefractory (NR) POM and NR (NH4)xHySO4 + H2O size distributions to calculate submicrometer light scattering (σsp) at a wavelength of 550 nm suggest that POM was a dominant chemical component contributing to aerosol light scattering (haze) during NEAQS 2002, and contributed 60 ± 6 % and 57 ± 11 % to σsp at 55% RH during two pollution episodes off the New England Coast. These results are similar to those from the mid‐Atlantic states during TARFOX but contrary to the long‐term monitoring measurements over the continental northeast United States that show the New England haze is primarily a result of sulfate aerosol.
α-Lithioalkoxysilanes, (RO)R
2′SiCH(Li)(R″) (R=Me, Et; R′=Me, Ph; R″=H, SiMe
3), can be prepared by treating the appropriate alkoxysilane with
tert-butyllithium in hydrocarbon solvents. For R=Me or ...Et, R′=Me, and R″=H or SiMe
3, the α-lithioalkoxysilanes are produced in high yield. Similar treatment of alkoxysilane
12, EtOPh
2SiCH
3, afforded the corresponding α-lithioalkoxysilane
13 (R=Et, R′=Ph and R″=H), in moderate yield, along with substitution product
14,
tert-BuPh
2SiCH
3. Analogous reactions with
n-butyl- and
sec-butyllithium in hydrocarbon solvent produced significant or exclusive substitution at silicon, rather than α-lithiation.
α-Lithioalkoxysilanes RO(Me
2)SiCH(Li)(X), where R=Me or Et and X=H or SiMe
3, react with carbonyl compounds in hydrocarbon solution to produce alkenes in moderate to high yield via Peterson-type ...reactions. For X=SiMe
3, the corresponding vinylsilanes are isolated directly following work-up. The reaction is regiospecific and shows fair stereoselectivity. When the carbonyl substrates are cyclic ketones in six- or seven-membered rings, the products are exocyclic alkenes. For X=H, the initial product is a β-hydroxysilane, which is then efficiently converted to the corresponding terminal alkene by heating with sodium acetate in acetic acid. Both types of α-lithioalkoxysilane reagents are amenable to reaction with enolizable carbonyl compounds.
In metropolitan Detroit, scholars have long observed that geographic space is racialized in the sense that black Americans are not welcome in many suburban communities. This extends beyond housing ...segregation: black drivers are not wanted on many suburban streets. While the existence of racial animosity has been documented, the enforcement mechanisms utilized to ‘protect’ certain geographic areas from black presence have rarely been quantified and dissected. This study examines police behavior toward black motorists who were arrested during routine traffic stops in the Detroit suburb of Eastpointe. Comparison of search, arrest, and handcuff patterns of white and black motorists indicates that police bias harms blacks. Rather than simply being anti‐black, patterns of police behavior in Eastpointe enforce racialized space, signaling where black presence is tolerated and where it is discouraged.
Depuis longtemps, les intellectuels observent la racialisation de l’espace géographique, au sens que les Américains noirs ne sont pas les bienvenus dans de nombreuses communautés de banlieue de la métropole de Détroit. La tendance dépasse la ségrégation des logements: les automobilistes noirs sont indésirables dans bien des rues de banlieue. Si l’existence d’une animosité raciale a été documentée, les mécanismes coercitifs utilisés pour ‘protéger’ certaines zones géographiques d’une présence noire ont rarement été quantifiés ou disséqués. Cette étude examine l’attitude policière vis‐à‐vis des conducteurs noirs arrêtés au cours de contrôles de routine dans la banlieue de Eastpointe, à Détroit. Une comparaison des types de fouilles, arrestations et menottages d’automobilistes blancs et noirs révèle un préjugé de la police au détriment des noirs. Au lieu d’être simplement anti‐noirs, les types de comportement policier à Eastpointe impose un espace racialisé, indiquant là où la présence noire est tolérée et là où elle est dissuadée.
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