This study investigates the diurnal migration of the low‐level jet (LLJ) over the Bay of Bengal in the summer monsoon, which remains understudied despite the well‐documented diurnal offshore ...propagation of rainfall worldwide. The southwesterly LLJ exhibits maximum strength during the night and morning. The LLJ undergoes a substantial eastward migration of approximately 600 km from the eastern offshore of India at midnight to the center of the Bay of Bengal by afternoon. A linear land‐sea breeze model is effective in capturing the diurnal migration with similar speed and phase. Including background wind offshore extends the migration, rather than confining it to the coast. This migration is driven by inertia‐gravity waves arising from the diurnal land‐sea thermal contrast and is influenced by the westerly upstream wind from the Indian subcontinent. Our results have important implications for understanding diurnal monsoon circulations and their associated precipitation.
Plain Language Summary
The low‐level jet (LLJ) in the summer monsoon plays a crucial role in affecting nocturnal downstream precipitation in South Asia. Previous studies have primarily concentrated on changes in the jet's strength during the day, neglecting its varying location. The present study addresses this gap by providing a comprehensive examination of the previously neglected aspect of the diurnal offshore migration of the LLJ over the Bay of Bengal. The diurnal migration is driven by the difference in temperature between the land and sea and is also aided by upstream wind, in a manner similar to the diurnal offshore propagation of rainfall. Overall, this study offers a more complete understanding of the LLJ' behaviors in the summer monsoon, which can help explain how it affects rainfall in the region.
Key Points
The monsoon low‐level jet migrates eastward from the eastern offshore of India at midnight to the center of the Bay of Bengal by afternoon
The offshore diurnal migration is driven by inertia‐gravity waves resulting from the diurnal thermal contrast between land and sea
The westerly upstream wind from the Indian subcontinent extends the offshore migration, rather than confining it to the coast
In this study, we report nonmetal plasmonic MoS2@TiO2 heterostructures for highly efficient photocatalytic H2 generation. Large area laminated MoS2 in conjunction with TiO2 nanocavity arrays is ...achieved via carefully controlled anodization, physical vapor deposition, and chemical vapor deposition processes. The broad spectral response ranging from ultraviolet-visible (UV-vis) to near-infrared (NIR) wavelengths and finite element frequency-domain simulations suggest that this MoS2@TiO2 heterostructure enhances photocatalytic activity for H+ reduction. A high H2 yield rate of 181 μmol h−1 cm−2 (equal to 580 mmol h−1 g−1 based on the loading mass of MoS2) is achieved using a low catalyst loading mass. The spatially uniform heterostructure, correlated with plasmon-resonance through the conformal MoS2 coating that effectively regulates charge transfer pathways, is proven to be vitally important for the unique solar energy harvesting and photocatalytic H2 production. As an innovative exploration, our study demonstrates that the photocatalytic activities of nonmetal, earth-abundant materials can be enhanced with plasmonic effects, which may serve as an excellent catalytic agent for solar energy conversion to chemical fuels.
To explore the characteristics of Helicobacter pylori resistance in China and the association between antibiotic resistance and several clinical factors.
H. pylori strains were collected from ...patients in 13 provinces or cities in China between 2010 and 2016. Demographic data including type of disease, geographic area, age, gender and isolation year were collected to analyse their association with antibiotic resistance. Antibiotic resistance was detected using the Etest test and the Kirby-Bauer disc diffusion method.
H. pylori were successfully cultured from 1117 patients. The prevalence of metronidazole, clarithromycin (CLA), azithromycin, levofloxacin (LEV), moxifloxacin, amoxicillin (AMO), tetracycline and rifampicin resistance was 78.2, 22.1, 23.3, 19.2, 17.2, 3.4, 1.9 and 1.5%, respectively. No resistance to furazolidone was observed. The resistance rates to LEV and moxifloxacin were higher in strains isolated from patients with gastritis compared to those with duodenal ulcer and among women. Compared to patients ≥40 years old, younger patients exhibited lower resistance rates to CLA, azithromycin, LEV and moxifloxacin. The resistance rates to CLA and AMO were higher in strains isolated more recently, and we also found that the prevalence of resistance to metronidazole, CLA, azithromycin and AMO were significantly different among different regions of China.
The resistance rates to metronidazole, CLA and LEV were high in China. Patient age, gender, disease and location were associated with the resistance of H. pylori to some antibiotics. Furazolidone, AMO and tetracycline are better choices for H. pylori treatment in China.
AbstractThe present study investigated the effectiveness of two soil-bentonite slurry wall backfills, specifically sand/conventional Na-bentonite (NaB) and sand/hexametaphosphate (SHMP)-amended ...Ca-bentonite (SHMP-CaB), for the containment of the coal combustion residuals (CCR) impacted groundwater. Several series of laboratory experiments were conducted to determine swell index, liquid limit, slump, hydraulic conductivity, and compressibility of the backfills using distilled water or tap water and simulated CCR impacted groundwater. The results showed that NaB exhibited a higher free swell index as compared with that of SHMP-CaB in both the CCR-impacted groundwater and the distilled water. Both NaB and SHMP-CaB possessed lower liquid limit values with the CCR-impacted groundwater. During the test duration of 96 days, the CCR-impacted groundwater caused 1.39 times increase in the short-term hydraulic conductivity of the sand/NaB backfill, while there was a 0.95–0.91 times decrease in the short-term hydraulic conductivity of the sand/SHMP-CaB backfill. The compression index and rebound index values of the tested backfills prepared with the CCR-impacted groundwater were lower than the backfills prepared with tap water. Scanning electron microscope analysis showed that SHMP promoted the Ca-bentonite to exist in more dispersed particle association with smaller particle size, resulting in the observed results for SHMP-CaB backfill. Additional research is recommended to assess long-term chemical compatibility of the backfills with CCR-impacted groundwater.
Biomass burning, the largest global source of elemental carbon (EC) and primary organic carbon (OC), is strongly associated with many subjects of great scientific concern, such as secondary organic ...aerosol and brown carbon which exert important effects on the environment and on climate in particular. This study investigated the relationships between levoglucosan and other biomass burning tracers (i.e., water soluble potassium and mannosan) based on both ambient samples collected in Beijing and source samples. Compared with North America and Europe, Beijing was characterized by high ambient levoglucosan concentrations and low winter to summer ratios of levoglucosan, indicating significant impact of biomass burning activities throughout the year in Beijing. Comparison of levoglucosan and water soluble potassium (K+) levels suggested that it was acceptable to use K+ as a biomass burning tracer during summer in Beijing, while the contribution of fireworks to K+ could be significant during winter. Moreover, the levoglucosan to K+ ratio was found to be lower during the typical summer period (0.21 ± 0.16) compared with the typical winter period (0.51 ± 0.15). Levoglucosan correlated strongly with mannosan (R2 = 0.97) throughout the winter and the levoglucosan to mannosan ratio averaged 9.49 ± 1.63, whereas levoglucosan and mannosan exhibited relatively weak correlation (R2 = 0.73) during the typical summer period when the levoglucosan to mannosan ratio averaged 12.65 ± 3.38. Results from positive matrix factorization (PMF) model analysis showed that about 50% of the OC and EC in Beijing were associated with biomass burning processes. In addition, a new source identification method was developed based on the comparison of the levoglucosan to K+ ratio and the levoglucosan to mannosan ratio among different types of biomass. Using this method, the major source of biomass burning aerosol in Beijing was suggested to be the combustion of crop residuals, while the contribution from softwood burning was also non-negligible, especially in winter.
Properties of atomic van der Waals heterostructures are profoundly influenced by interlayer coupling, which critically depends on stacking of the proximal layers. Rotational misalignment or lattice ...mismatch of the layers gives rise to a periodic modulation of the stacking, the moiré superlattice. Provided the superlattice period extends over many unit cells, the coupled layers undergo lattice relaxation, leading to the concentration of strain at line defects - solitons - separating large area commensurate domains. We visualize such long-range periodic superstructures in thin crystals of hexagonal boron nitride using atomic-force microscopy and nano-infrared spectroscopy. The solitons form sub-surface hexagonal networks with periods of a few hundred nanometers. We analyze the topography and infrared contrast of these networks to obtain spatial distribution of local strain and its effect on the infrared-active phonons of hBN.
Summary
Objective
To quantify the association between maternal pre‐pregnancy body mass index (BMI) and perinatal outcomes.
Methods
We systematically reviewed and collected studies on maternal ...pre‐pregnancy BMI and perinatal outcomes published up to 31 August 2015. For each study, we constructed separate two‐by‐two tables to calculate the odds ratios (ORs) and 95% confidence intervals (CI).
Results
A total of 60 studies involving 1,392,799 women were included, and the proportions of obesity, overweight, normal weight and underweight pregnant women were 11.72%, 22.08%, 58.03% and 8.18%, respectively. When mothers were overweight or obese, their infants had a significantly higher risk of being large for gestational age (OR, 1.45, 95%CI, 1.29–1.63 and 1.88, 95%CI, 1.67–2.11, respectively), having macrosomia (OR, 1.70, 95%CI, 1.55–1.87 and 2.92, 95%CI, 2.67–3.20, respectively), being admitted to the neonatal intensive care unit (OR, 1.29, 95%CI, 1.12–1.48 and 1.91, 95%CI, 1.60–2.29, respectively) and being stillborn (OR, 1.27, 95%CI, 1.18–1.36 and 1.81, 95%CI, 1.69–1.93, respectively). When mothers were underweight, their infants had a lower risk of the aforementioned outcomes. However, mothers who were underweight had a higher risk of preterm birth (OR, 1.30, 95%CI, 1.13–1.49) and delivering an infant small for gestational age (OR, 1.67, 95%CI, 1.49–1.87). Importantly, infants had a higher risk of having a low birth weight (LBW) when their mothers were underweight (OR, 1.67, 95%CI, 1.39–2.02) or obese (OR, 1.24, 95%CI, 1.09–1.41).
Conclusion
Being overweight or obese was associated with an increased risk of still birth, large for gestational age, macrosomia, admission to the neonatal intensive care unit and LBW, while being underweight was associated with an increased risk of preterm birth, small for gestational age, and LBW. Women of childbearing age should maintain a normal body mass index before pregnancy.
Highlights • Developmental disruptions of serotonin signaling involved in autism. • Hyperserotonemia provokes a loss of serotonin terminals. • Deficiency of the serotonergic system induces mis-wiring ...of neural network.
Development of efficient and durable oxygen evolution reaction (OER) catalysts has a direct impact on the water splitting efficiency and cost effectiveness. In this work, we report the successful ...synthesis of a new Ni(OH)
2
structure, strain-stabilized Ni(OH)
2
nanoribbons (NR-Ni(OH)
2
) two to three layers thick, with widths of 2-5 nm,
via
an electro-oxidation route. Conventional Ni(OH)
2
usually has negligible OER activity, while NR-Ni(OH)
2
shows high activity for the oxygen evolution reaction and an overpotential of 162 millivolts and furthermore exhibits long-term stability in alkaline electrolyte. The substantial reduction in the overpotential of NR-Ni(OH)
2
is due to its easier OOH* adsorption by the active four-coordinated Ni edge sites. The enhanced catalytic activity of NR-Ni(OH)
2
makes it an excellent candidate for industrial applications.
Development of efficient and durable oxygen evolution reaction (OER) catalysts has a direct impact on the water splitting efficiency and cost effectiveness.
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