1,440 research outputs found
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Evaluation of simulated O-3 production efficiency during the KORUS-AQ campaign: Implications for anthropogenic NOx emissions in Korea
We examine O3 production and its sensitivity to precursor gases and boundary layer mixing in Korea by using a 3-D global chemistry transport model and extensive observations during the KORea-US cooperative Air Quality field study in Korea, which occurred in MayâJune 2016. During the campaign, observed aromatic species onboard the NASA DC-8 aircraft, especially toluene, showed high mixing ratios of up to 10 ppbv, emphasizing the importance of aromatic chemistry in O3 production. To examine the role of VOCs and NOx in O3 chemistry, we first implement a detailed aromatic chemistry scheme in the model, which reduces the normalized mean bias of simulated O3 mixing ratios from â26% to â13%. Aromatic chemistry also increases the average net O3 production in Korea by 37%. Corrections of daytime PBL heights, which are overestimated in the model compared to lidar observations, increase the net O3 production rate by ~10%. In addition, increasing NOx emissions by 50% in the model shows best performance in reproducing O3 production characteristics, which implies that NOx emissions are underestimated in the current emissions inventory. Sensitivity tests show that a 30% decrease in anthropogenic NOx emissions in Korea increases the O3 production efficiency throughout the country, making rural regions ~2 times more efficient in producing O3 per NOx consumed. Simulated O3 levels overall decrease in the peninsula except for urban and other industrial areas, with the largest increase (~6 ppbv) in the Seoul Metropolitan Area (SMA). However, with simultaneous reductions in both NOx and VOCs emissions by 30%, O3 decreases in most of the country, including the SMA. This implies the importance of concurrent emission reductions for both NOx and VOCs in order to effectively reduce O3 levels in Korea
Survival of outborns with congenital diaphragmatic hernia: the role of protective ventilation, early presentation and transport distance: a retrospective cohort study
BACKGROUND:
Congenital diaphragmatic hernia (CDH) is a congenital malformation associated with life-threatening pulmonary dysfunction and high neonatal mortality. Outcomes are improved with protective ventilation, less severe pulmonary pathology, and the proximity of the treating center to the site of delivery. The major CDH treatment center in Croatia lacks a maternity ward, thus all CDH patients are transferred from local Zagreb hospitals or remote areas (outborns). In 2000 this center adopted protective ventilation for CDH management. In the present study we assess the roles of protective ventilation, transport distance, and severity of pulmonary pathology on survival of neonates with CDH. ----- METHODS:
The study was divided into Epoch I, (1990-1999, traditional ventilation to achieve normocapnia), and Epoch II, (2000-2014, protective ventilation with permissive hypercapnia). Patients were categorized by transfer distance (local hospital or remote locations) and by acuity of respiratory distress after delivery (early presentation-occurring at birth, or late presentation, â„ 6 h after delivery). Survival between epochs, types of transfers, and acuity of presentation were assessed. An additional analysis was assessed for the potential association between survival and end-capillary blood CO2 (PcCO2), an indirect measure of pulmonary pathology. ----- RESULTS:
There were 83 neonates, 26 in Epoch I, and 57 in Epoch II. In Epoch I 11 patients (42%) survived, and in Epoch II 38 (67%) (P = 0.039). Survival with early presentation (N = 63) was 48 % and with late presentation 95% (P <0.001). Among early presentation, survival was higher in Epoch II vs. Epoch I (57% vs. 26%, P = 0.031). From multiple logistic regression analysis restricted to neonates with early presentation and adjusting for severity of disease, survival was improved in Epoch II (OR 4.8, 95%CI 1.3-18.0, P = 0.019). Survival was unrelated to distance of transfer but improved with lower partial pressure of PcCO2 on admission (OR 1.16, 95%CI 1.01-1.33 per 5 mmHg decrease, P = 0.031). ----- CONCLUSIONS:
The introduction of protective ventilation was associated with improved survival in neonates with early presentation. Survival did not differ between local and remote transfers, but primarily depended on severity of pulmonary pathology as inferred from admission capillary PcCO2
Unweaving the population structure and genetic diversity of Canadian shrub willow
Perennial shrub willow are increasingly being promoted in short-rotation coppice systems as biomass feedstocks, for phytoremediation applications, and for the diverse ecosystem services that can accrue. This renewed interest has led to widespread willow cultivation, particularly of non-native varieties. However, Canadian willow species have not been widely adopted and their inherent diversity has not yet been thoroughly investigated. In this study, 324 genotypes of Salix famelica and Salix eriocephala collected from 33 sites of origin were analyzed using 26,016 single nucleotide polymorphisms to reveal patterns of population structure and genetic diversity. Analyses by Bayesian methods and principal component analysis detected five main clusters that appeared to be largely shaped by geoclimatic variables including mean annual precipitation and the number of frost-free days. The overall observed (HO) and expected (HE) heterozygosity were 0.126 and 0.179, respectively. An analysis of molecular variance revealed that the highest genetic variation occurred within genotypes (69%), while 8% of the variation existed among clusters and 23% between genotypes within clusters. These findings provide new insights into the extent of genetic variation that exists within native shrub willow species which could be leveraged in pan-Canadian willow breeding programs.Fil: Murphy, Emily K. University of British Columbia. Faculty of Forestry. Department of Wood Science; CanadĂĄFil: Cappa, Eduardo Pablo. Instituto Nacional de TecnologĂa Agropecuaria (INTA). Instituto de Recursos BiolĂłgicos; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Soolanayakanahally, Raju Y. Agriculture and Agri-Food Canada. Indian Head Research Farm; CanadĂĄ.
Agriculture and Agri-Food Canada. Saskatoon Research and Development Centre; CanadĂĄ.Fil: El-Kassaby, Yousry A. University of British Columbia. Faculty of Forestry. Department of Forest and Conservation Sciences; CanadĂĄFil: Parkin, Isobel A.P. Agriculture and Agri-Food Canada. Saskatoon Research and Development Centre; CanadĂĄ.Fil: Schroeder, William R. Agriculture and Agri-Food Canada. Indian Head Research Farm; CanadĂĄFil: Mansfield, Shawn D. University of British Columbia. Faculty of Forestry. Department of Wood Science; Canad
Solid malignancies among etanerceptâtreated patients with granulomatosis with polyangiitis (Wegener's): Longâterm followup of a multicenter longitudinal cohort
Objective An association between therapeutic inhibition of tumor necrosis factor (TNF) and solid malignancies was observed during the Wegener's Granulomatosis Etanercept Trial (WGET), which included 180 patients with granulomatosis with polyangiitis (Wegener's) (GPA). The present study was conducted to determine the malignancy risk beyond the time of exposure to study therapy. Methods The occurrence and type of solid malignancies were ascertained using a standardized data form. Data collected included vital status, histologic findings, and therapeutic interventions. The Surveillance, Epidemiology, and EndâResults database was used to estimate a standardized incidence rate (SIR) for solid malignancies. Results Postâtrial followup data were available for 153 patients (85% of the original cohort), with a median followup time of 43 months. Fifty percent of these patients had received etanercept. There were no differences in demographic characteristics between the etanercept and placebo groups. Thirteen new solid malignancies were detected, 8 in the etanercept group and 5 in the placebo group. Compared to the general population, the risk of solid malignancies in the etanercept group was increased (SIR 3.92 [95% confidence interval 1.69â7.72]), but was not different from the risk in the placebo group compared to the general population (SIR 2.89 [95% confidence interval 0.94â6.73]). All solid malignancies occurred in patients who had been exposed to cyclophosphamide. The overall duration of disease and a history of malignancy before trial enrollment were associated with the development of malignancy during postâtrial followup. Conclusion The incidence of solid malignancy remained increased during longâterm followup of the WGET cohort. However, this could not be attributed solely to etanercept exposure during the trial. AntiâTNF therapy with etanercept appears to further increase the risk of malignancy observed in patients with GPA treated with cytotoxic agents and should be avoided in these patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87143/1/30394_ftp.pd
Centimeter to decimeter hollow concretions and voids in Gale Crater sediments, Mars
Voids and hollow spheroids between âŒ1 and 23 cm in diameter occur at several locations along the traverse of the Curiosity rover in Gale crater, Mars. These hollow spherical features are significantly different from anything observed in previous landed missions. The voids appear in dark-toned, rough-textured outcrops, most notably at Point Lake (sols 302-305) and Twin Cairns Island (sol 343). Point Lake displays both voids and cemented spheroids in close proximity; other locations show one or the other form. The spheroids have 1-4 mm thick walls and appear relatively dark-toned in all cases, some with a reddish hue. Only one hollow spheroid (Winnipesaukee, sol 653) was analyzed for composition, appearing mafic (Fe-rich), in contrast to the relatively felsic host rock. The interior surface of the spheroid appears to have a similar composition to the exterior with the possible exceptions of being more hydrated and slightly depleted in Fe and K. Origins of the spheroids as Martian tektites or volcanic bombs appear unlikely due to their hollow and relatively fragile nature and the absence of in-place clearly igneous rocks. A more likely explanation to both the voids and the hollow spheroids is reaction of reduced iron with oxidizing groundwater followed by some re-precipitation as cemented rind concretions at a chemical reaction front. Although some terrestrial concretion analogs are produced from a precursor siderite or pyrite, diagenetic minerals could also be direct precipitates for other terrestrial concretions. The Gale sediments differ from terrestrial sandstones in their high initial iron content, perhaps facilitating a higher occurrence of such diagenetic reactions
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Pressure gradient passivation of carbonaceous material normally susceptible to spontaneous combustion
This invention is a process for the passivation or deactivation with respect to oxygen of a carbonaceous material by the exposure of the carbonaceous material to an oxygenated gas in which the oxygenated gas pressure is increased from a first pressure to a second pressure and then the pressure is changed to a third pressure. Preferably a cyclic process which comprises exposing the carbonaceous material to the gas at low pressure and increasing the pressure to a second higher pressure and then returning the pressure to a lower pressure is used. The cycle is repeated at least twice wherein the higher pressure may be increased after a selected number of cycles
Metabolic analysis of the interaction between plants and herbivores
Insect herbivores by necessity have to deal with a large arsenal of plant defence metabolites. The levels of defence compounds may be increased by insect damage. These induced plant responses may also affect the metabolism and performance of successive insect herbivores. As the chemical nature of induced responses is largely unknown, global metabolomic analyses are a valuable tool to gain more insight into the metabolites possibly involved in such interactions. This study analyzed the interaction between feral cabbage (Brassica oleracea) and small cabbage white caterpillars (Pieris rapae) and how previous attacks to the plant affect the caterpillar metabolism. Because plants may be induced by shoot and root herbivory, we compared shoot and root induction by treating the plants on either plant part with jasmonic acid. Extracts of the plants and the caterpillars were chemically analysed using Ultra Performance Liquid Chromatography/Time of Flight Mass Spectrometry (UPLCT/MS). The study revealed that the levels of three structurally related coumaroylquinic acids were elevated in plants treated on the shoot. The levels of these compounds in plants and caterpillars were highly correlated: these compounds were defined as the âmetabolic interfaceâ. The role of these metabolites could only be discovered using simultaneous analysis of the plant and caterpillar metabolomes. We conclude that a metabolomics approach is useful in discovering unexpected bioactive compounds involved in ecological interactions between plants and their herbivores and higher trophic levels.
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