Improved estimation of the effective reproduction number with heterogeneous transmission rates and reporting delays.

In the face of an infectious disease, a key epidemiological measure is the basic reproduction number, which quantifies the average secondary infections caused by a single case in a susceptible population. In practice, the effective reproduction number, denoted as , is widely used to assess the transmissibility of the disease at a given time t. Real-time estimating this metric is vital for understanding and managing disease outbreaks.

Boosting oxygen reduction durability by embedding CoS nanoparticles into Co single atoms anchored porous carbon frameworks.

Developing an efficient and low-cost oxygen reduction electrocatalyst is essential for the application of aqueous zinc-air batteries (ZABs). Herein, we report a facile adsorption-confined pyrolysis strategy to fabricate the hybrid electrocatalyst (denoted as CoS/Co-PC) by embedding CoS nanoparticles into Co single atoms (Co-SAs) anchored porous carbon sheets for boosting oxygen reduction reaction (ORR) durability. In this strategy, the Co ions are first absorbed into oxygen-rich porous carbon nanosheets and further form the Co-SAs with the help of thiourea in the following pyrolysis procedure, which is believed to be able to confine the generated CoS nanoparticles into carbon frameworks due to their interface interaction.

Accelerating Sulfur Redox Chemistry by Atomically Dispersed Zn-N Sites Coupled with Pyridine-N Defects on Porous Carbon Sheets.

Single-atom catalysts (SACs) with specific N-coordinated configurations immobilized on the carbon substrates have recently been verified to effectively alleviate the shuttle effect of lithium polysulfides (LiPSs) in lithium-sulfur (Li─S) batteries. Herein, a versatile molten salt (KCl/ZnCl )-mediated pyrolysis strategy is demonstrated to fabricate Zn SACs composed of well-defined Zn-N sites embedded into porous carbon sheets with rich pyridine-N defects (Zn─N/CS). The electrochemical kinetic analysis and theoretical calculations reveal the critical roles of Zn-N active sites and surrounding pyridine-N defects in enhancing adsorption toward LiPS intermediates and catalyzing their liquid-solid conversion.

Nano silicon dioxide reduces cadmium uptake, regulates nutritional homeostasis and antioxidative enzyme system in barley seedlings (Hordeum vulgare L.) under cadmium stress.

Cadmium (Cd) toxicity is one of the most severe environmental threats inhibiting crop growth and productivity. Strategies to mitigate the adverse effects of Cd stress on plants are under scrutiny. Nano silicon dioxide (nSiO) is an emerging material and could protect plants against abiotic stress.

Potential methane production in oligohaline wetlands undergoing erosion and accretion in the Mississippi River Delta Plain, Louisiana, USA.

Methane (CH) is steadily increasing in the atmosphere from different sources including wetlands. However, there is limited landscape level CH flux data in deltaic coastal systems where the availability of freshwater is impacted by the combined effect of climate change and anthropogenic impacts. Here we determine potential CH fluxes in oligohaline wetlands and benthic sediments in the Mississippi River Delta Plain (MRDP), which is undergoing the highest rate of wetland loss and most extensive hydrological wetland restoration in North America.

Metals geochemistry and mass export from the Mississippi-Atchafalaya River system to the Northern Gulf of Mexico.

Discharging 680 km of freshwater annually to the Northern Gulf of Mexico (NGOM), the Mississippi-Atchafalaya River System (MARS) plays a significant role in transporting major and trace elements to the ocean. In this study, we analyzed total recoverable concentrations of thirty-one metals from water samples collected at five locations along the MARS during 2013-2016 to quantify their seasonal mass exports. The Atchafalaya River flows through a large swamp floodplain, allowing us to also test the hypothesis that floodplains function as a sink for metals.

Three decadal inputs of total organic carbon from four major coastal river basins to the summer hypoxic zone of the Northern Gulf of Mexico.

This study investigated long-term (1980-2009) yields and variability of total organic carbon (TOC) from four major coastal rivers in Louisiana entering the Northern Gulf of Mexico where a large-area summer hypoxic zone has been occurring since the middle 1980s. Two of these rivers drain agriculture-intensive (>40%) watersheds, while the other two rivers drain forest-pasture dominated (>50%) watersheds. The study found that these rivers discharged a total of 13.

[Comparative study of the level and distribution of polybrominated diphenyl ethers and new brominated flame retardants in the atmosphere of typical urban].

Brominated flame retardants (BFRs) are widely used in industrial and commercial products and are frequently detected in various environmental media. It might be potential harm to the environment and the human body. This study reported the levels of 8 kinds of polybrominated diphenyl ethers (PBDEs: BDE-28, -47, -100, -99, -154, -153, -183, -209) and 3 kinds of new brominated flame retardants (NBFRs: PBT, PBEB, HBB) in the atmosphere of Binhai Development Zone, Weifang City, Shandong Province, which was taken as a BFR production source area and of Nanning City, Guangxi Province, which was taken as a contrast area.

Polybrominated diphenyl ethers, dechlorane plus, and polychlorinated biphenyls in tree bark near the upper Yellow River, China.

Willow tree bark samples from urban and rural sites in Inner Mongolia, Ningxia Province, and Gansu Province, in the Yellow River basin, were analyzed for polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), and dioxin-like polychlorinated biphenyls (DL-PCBs) to compare their relative levels in air in these areas (i.e., treating bark as a passive air sampler).

Concentrations and relationships between classes of persistent halogenated organic compounds in pooled human serum samples and air from Laizhou Bay, China.

Persistent halogenated organic compounds, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), pentabromobenzene (PBBz), and pentabromotoluene (PBT), were analyzed in pooled human serum samples from different age groups and air samples from the south coast of Laizhou Bay, Shandong Province, China. The ∑25OCP and ∑8PBDE congeners were found at higher concentrations than the other compounds, with mean concentrations of 1500 and 240ng/g lipid in serum and 330 and 140,000pg/m(3) in the air, respectively. PBBz and PBT were detected in every serum and air sample, with mean concentrations of 4.

[Vertical distribution of PBDEs and DL-PCBs in sediments of Taihu Lake].

Sediment core samples collected from the Zhushan Bay, Meiliang Bay, South Taihu of Taihu Lake were analyzed for 8 polybrominated diphenylethers (PBDEs) and 12 dioxin-like PCBs (DL-PCBs). The results revealed that the PBDEs levels were highest in the Zhushan Bay, followed by Meiliang Bay and South Taihu; and the DL-PCB levels were highest in the Meiliang Bay, followed Zhushan Bay and South Taihu. The vertical distribution of PBDEs level showed an exponential growth trend in Taihu Lake sediments, BDE-209 was the most abundant PBDEs congeners; and the vertical distribution of the DL-PCBs level in the sediments revealed that the contamination caused by DL-PCBs continued to increase in recent years, indicating that there were PCBs sources in the Taihu Lake region.

Concentrations and trends of halogenated flame retardants in the pooled serum of residents of Laizhou Bay, China.

The south coast of Laizhou Bay, in northeastern China, is a production area for halogenated flame retardants (HFR). In 2007, the authors measured serum concentrations of polybrominated diphenyl ethers (PBDEs) in Laizhou Bay residents. To assess the PBDE concentration trend, and determine the concentrations of the emerging flame retardants Dechlorane Plus (DP) and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH), the authors measured the concentrations of 8 PBDE congeners, 2 DP isomers, and TBPH in 10 composite samples, which were pooled from the serum collected from 305 Laizhou Bay residents in October 2011.