The Distances to Molecular Clouds at High Galactic Latitudes based on GAIA DR2

We report the distances of molecular clouds at high Galactic latitudes (|b|>10$^\circ$) derived from parallax and G band extinction (A$_{\rm G}$) measurements in the second Gaia data release, Gaia DR2. Aided by Bayesian analyses, we determined distances by identifying the breakpoint in the extinction A$_{\rm G}$ towards molecular clouds and using the extinction A$_{\rm G}$ of Gaia stars around molecular clouds to confirm the breakpoint. We use nearby star-forming regions, such as Orion, Taurus, Cepheus, and Perseus, whose distances are well-known to examine the reliability of our method. By comparing with previous results, we found that the molecular cloud distances derived from this method are reliable. The systematic error in the distances is approximately 5%. In total, 52 molecular clouds have their distances well determined, most of which are at high Galactic latitudes, and we provide reliable distances for 13 molecular clouds for the first time.Comment: Accepted by A&A. 13 pages, 9 figure

Time to full enteral feeding for very low-birth-weight infants varies markedly among hospitals worldwide but may not be associated with incidence of necrotizing enterocolitis:The NEOMUNE-NeoNutriNet Cohort Study

Background: Transition to enteral feeding is difficult for very low-birth-weight (VLBW; ≤1500 g) infants, and optimal nutrition is important for clinical outcomes. Method: Data on feeding practices and short-term clinical outcomes (growth, necrotizing enterocolitis [NEC], mortality) in VLBW infants were collected from 13 neonatal intensive care units (NICUs) in 5 continents (n = 2947). Specifically, 5 NICUs in Guangdong province in China (GD), mainly using formula feeding and slow feeding advancement (n = 1366), were compared with the remaining NICUs (non-GD, n = 1581, Oceania, Europe, United States, Taiwan, Africa) using mainly human milk with faster advancement rates. Results: Across NICUs, large differences were observed for time to reach full enteral feeding (TFF; 8–33 days), weight gain (5.0–14.6 g/kg/day), ∆z-scores (−0.54 to −1.64), incidence of NEC (1%–13%), and mortality (1%–18%). Adjusted for gestational age, GD units had longer TFF (26 vs 11 days), lower weight gain (8.7 vs 10.9 g/kg/day), and more days on antibiotics (17 vs 11 days; all P <.001) than non-GD units, but NEC incidence and mortality were similar. Conclusion: Feeding practices for VLBW infants vary markedly around the world. Use of formula and long TFF in South China was associated with more use of antibiotics and slower weight gain, but apparently not with more NEC or higher mortality. Both infant- and hospital-related factors influence feeding practices for preterm infants. Multicenter, randomized controlled trials are required to identify the optimal feeding strategy during the first weeks of life

Marine Ecological Risk Assessment Methods for Radiation Accidents

Ecological risk assessment (ERA) is a powerful technical tool that can be used to analyze potential and extreme adverse environmental impacts. With the rapid development of nuclear power plants in coastal areas around the world, the establishment of approaches and methodologies for marine ERA with a focus on radiation accidents is an urgent requirement for marine environmental management. In this study, the approaches and methodologies for ERA pertaining to marine radiation accidents (MRA) are discussed and summarized with applications in case studies, such as the nuclear accident in Fukushima, Japan, and a hypothetical accident in Daya Bay, China. The concepts of ERA and Risk Degree of ERA on MRA are defined for the first time to optimize the ERA system. The results of case studies show that the ERA approach and methodology for MRA are scientifically sound and effective in both the early and late stage of MRAs along with classic ERA Approach and the ERICA Integrated Approach. The results can be useful in the decision-making processes and the risk management at the beginning of accident as well as the ecological restoration after the accident

Boron-modified chlorine-free K+-FeOx/SBA-15 as highly effective catalyst for propylene epoxidation by nitrous oxide

Modification of chlorine-free alkali metal ion (K+, Rb+, or Cs+)-containing FeOx/SBA-15 catalysts with boron enhanced their catalytic performances in propylene epoxidation by nitrous oxide. A B-K+-FeOx/SBA-15 catalyst (K/Fe = 2.5, B/Fe = 0.5) showed the best propylene oxide (PO) formation activity, providing PO selectivities of 79 and 55% at propylene conversions of 4.8 and 13% at 350 and 400 degrees C, respectively

Low Cost Test Pattern Generation in Scan-Based BIST Schemes

This paper proposes a low-cost test pattern generator for scan-based built-in self-test (BIST) schemes. Our method generates broadcast-based multiple single input change (BMSIC) vectors to fill more scan chains. The proposed algorithm, BMSIC-TPG, is based on our previous work multiple single-input change (MSIC)-TPG. The broadcast circuit expends MSIC vectors, so that the hardware overhead of the test pattern generation circuit is reduced. Simulation results with ISCAS&rsquo;89 benchmarks and a comparison with the MSIC-TPG circuit show that the proposed BMSIC-TPG reduces the circuit hardware overhead about 50% with ensuring of low power consumption and high fault coverage

Multi-dimensional visualization of ingestion, biological effects and interactions of microplastics and a representative POP in edible jellyfish

Due to their ubiquity and potential risks, microplastics (MPs) and nanoplastics (NPs) are concerning environmental issues. Yet there are still significant knowledge gaps in understanding the tissue-specific accumulation and dynamic change of MPs and NPs in the aquatic organism and how these micro/nano-scale emerging contaminants interact with other environmental pollutants such as persistent organic pollutants (POPs). Here, in vivo imaging systems (IVIS), radioisotope tracing, and histological staining were innovatively used to reveal the fate and toxicity of fluorescently-labeled MPs/NPs and 14C-labeled 2,4,4′-trichlorobiphenyl (PCB28) in edible jellyfish Rhopilema esculentum. These contaminants' ingestion, biological effects, and interactions were visualized at cellular, tissue, and whole-body multidimensional levels. Both MPs and NPs were shown to be preferentially accumulated in the mouthlets of oral arms, and most ingested MPs/NPs were present in the extracellular environment instead of being internalized into the mesoglea. Moreover, the presence of MPs or NPs in the seawater significantly inhibited the bioaccumulation of PCB28 in the jellyfish tissue, thus alleviating physiological alteration, gastric damage, and apoptosis caused by PCB28. This study provides a multi-dimensional visualization strategy to display the distribution and biological effects of typical pollutants in marine organisms and offers new insights for understanding the impacts of MPs/NPs and POPs on marine ecosystems

Iron-catalyzed propylene epoxidation by nitrous oxide: Effect of boron on structure and catalytic behavior of alkali metal ion-modified FeOx/SBA-15

The presence of boron significantly promoted propylene oxide (PO) formation over chlorine-free K+-modified FeOx/SBA-15 catalysts with K/Fe ratios >= 2.5. Boron also improved the catalytic performances of Rb+- and Cs+-modified FeOx/SBA-15 catalysts, whereas it did not play significant roles over Li+- and Na+-modified catalysts. Boron-promoted K+-FeOx/SBA-15 exhibited the best catalytic performance for PO formation. Potassium ions could enhance the dispersion of FeOx clusters, forming active iron sites. The addition of K+ at a higher content destroyed the ordered mesoporous structure of SBA-15, likely causing the reaggregation of iron species. The modification by boron could keep the ordered mesoporous structure and the high dispersion of iron species, which were beneficial to PO formation. The addition of boron with a proper content also suppressed further conversion of PO by diminishing the acidity and basicity of the catalyst. We propose that the interactions among boron, potassium ions, and iron species play pivotal roles in enhancing PO formation. (C) 2008 Elsevier Inc. All rights reserved

Iron-catalyzed propylene epoxidation by nitrous oxide: Studies on the effects of alkali metal salts

SBA-15-supported iron catalysts with and without alkali metal salt modifications were studied for propylene oxidation by nitrous oxide. The reaction route could be dramatically changed from allylic oxidation to epoxidation by modification of the FeOx/SBA-15 catalyst with alkali metal salts. The KCI-1 wt % FeOx/SBA-15 (K/Fe = 5) catalyst exhibited the best catalytic performances for propylene epoxidation, over which ca. 50% propylene oxide selectivity could be gained at a 10% propylene conversion at 648 K. Characterizations with diffuse reflectance UV-Vis, XANES, and Raman spectroscopic techniques revealed that the modification with KCl increased the dispersion of the iron species and changed the local coordination of iron into a tetrahedral configuration on the inner surface of SBA-15. This tetrahedrally coordinated iron site, which was probably stabilized by potassium ions, was proposed to account for the epoxidation of propylene by nitrous oxide. At the same time, the reactivity of lattice oxygen was inhibited, and the acidity of the FeOx/SBA-15 was eliminated. These changes should also contribute to the increase in the selectivity to propylene oxide. The counteranions in the alkali metal salts exerted a significant influence on the catalytic behaviors probably via an electronic effect

Combination of High Specific Activity Carbon-14 Labeling and High Resolution Mass Spectrometry to Study Pesticide Metabolism in Crops: Metabolism of Cycloxaprid in Rice

The study of pesticide metabolism in crops is critical for assessing the mode of action and environmental risks of pesticides. However, the study of pesticide metabolism in crops is usually complicated and it is often a daunting challenge to accurately screen the metabolites of novel pesticides in complex matrices. This study demonstrated a combined use of high-specific activity carbon-14 labeling and high-resolution mass spectrometry (HSA-14C-HRMS) for metabolism profiling of a novel neonicotinoid cycloxaprid in rice. By generating the characteristic radioactive peaks on the liquid chromatogram, the use of 14C can eliminate the severe interference of complex matrices and quickly probe target compounds; by producing ion pairs with unique abundance ratios on HRMS, high-specific activity labeling can effectively exclude false matrix positives and promote the elucidation of metabolite structure. The structures of 15 metabolites were identified, three of which were further confirmed by authentic standards. Based on these metabolites, a metabolic profile of cycloxaprid was established, which includes denitrification, demethylation, imidazolidine hydroxylation and ring cleavage olefin formation, oxidation and carboxylation reactions. The strategy of combining high-specific activity 14C labeling and HRMS offers unique advantages and provides a powerful solution for profiling unknown metabolites of novel pesticides in complex matrices, especially when traditional non-labeling methods are not feasible

Examining the Impact of Tropical Cyclones on Air-Sea CO2 Exchanges in the Bay of Bengal Based on Satellite Data and In Situ Observations

The impact of tropical cyclones (TCs) on the CO2 partial pressure at the sea surface (pCO(2sea)) and air-sea CO2 flux (F-CO2) in the Bay of Bengal (BoB) was quantified based on satellite data and in situ observations between November 2013 and January 2017. The in situ observations were made at the BoB Ocean Acidification mooring buoy. A weak time-mean net source of 55.78 +/- 11.16 mmol CO2 m(-2) year(-1) at the BoB Ocean Acidification site was estimated during this period. A wide range in increases of pCO(2sea) (1.0-14.8 mu atm) induced by TCs occurred in postmonsoon (October-December), and large decreases of pCO(2sea) (-14.0 mu atm) occurred in premonsoon (March-May). Large vertical differences in the ratio of dissolved inorganic carbon (DIC) to total alkalinity (TA) in the upper layer (Delta DIC/TA) were responsible for increasing pCO(2sea) in postmonsoon. Relatively small values of Delta DIC/TA were responsible for decreasing pCO(2sea) in premonsoon. Five TCs (Hudhud, Five, Kyant, Vardah, and Roanu) were considered. Hudhud significantly enhanced CO2 efflux (18.49 +/- 3.70 mmol CO2/m(2)) in oversaturated areas due to the wind effect during the storm and wind-pump effects after the storm. Vardah insignificantly changed F-CO2 (1.22 +/- 0.24 mmol CO2/m(2)) in undersaturated areas because of the counteraction of these two effects. Roanu significantly enhanced CO2 efflux (19.08 +/- 3.82 mmol CO2/m(2)) in highly oversaturated conditions (Delta pCO(2) > 20 mu atm) since the wind effect greatly exceeded the wind-pump effects. These five TCs were estimated to account for 55 +/- 23% of the annual-mean CO2 annual efflux, suggesting that TCs have significant impacts on the carbon cycle in the BoB