Validation of 7 Years in-Flight HY-2A Calibration Microwave Radiometer Products Using Numerical Weather Model and Radiosondes

Haiyang-2A (HY-2A) has been working in-flight for over seven years, and the accuracy of HY-2A calibration microwave radiometer (CMR) data is extremely important for the wet troposphere delay correction (WTC) in sea surface height (SSH) determination. We present a comprehensive evaluation of the HY-2A CMR observation using the numerical weather model (NWM) for all the data available period from October 2011 to February 2018, including the WTC and the precipitable water vapor (PWV). The ERA(ECMWF Re-Analysis)-Interim products from European Centre for Medium-Range Weather Forecasts (ECMWF) are used for the validation of HY-2A WTC and PWV products. In general, a global agreement of root-mean-square (RMS) of 2.3 cm in WTC and 3.6 mm in PWV are demonstrated between HY-2A observation and ERA-Interim products. Systematic biases are revealed where before 2014 there was a positive WTC/PWV bias and after that, a negative one. Spatially, HY-2A CMR products show a larger bias in polar regions compared with mid-latitude regions and tropical regions and agree better in the Antarctic than in the Arctic with NWM. Moreover, HY-2A CMR products have larger biases in the coastal area, which are all caused by the brightness temperature (TB) contamination from land or sea ice. Temporally, the WTC/PWV biases increase from October 2011 to March 2014 with a systematic bias over 1 cm in WTC and 2 mm in PWV, and the maximum RMS values of 4.62 cm in WTC and 7.61 mm in PWV occur in August 2013, which is because of the unsuitable retrieval coefficients and systematic TB measurements biases from 37 GHz band. After April 2014, the TB bias is corrected, HY-2A CMR products agree very well with NWM from April 2014 to May 2017 with the average RMS of 1.68 cm in WTC and 2.65 mm in PWV. However, since June 2017, TB measurements from the 18.7 GHz band become unstable, which led to the huge differences between HY-2A CMR products and the NWM with an average RMS of 2.62 cm in WTC and 4.33 mm in PWV. HY-2A CMR shows high accuracy when three bands work normally and further calibration for HY-2A CMR is in urgent need. Furtherly, 137 global coastal radiosonde stations were used to validate HY-2A CMR. The validation based on radiosonde data shows the same variation trend in time of HY-2A CMR compared to the results from ECMWF, which verifies the results from ECMWF

Generalist taxa shape fungal community structure in cropping ecosystems

Fungi regulate nutrient cycling, decomposition, symbiosis, and pathogenicity in cropland soils. However, the relative importance of generalist and specialist taxa in structuring soil fungal community remains largely unresolved. We hypothesized that generalist fungi, which are adaptable to various environmental conditions, could potentially dominate the community and become the basis for fungal coexisting networks in cropping systems. In this study, we identified the generalist and habitat specialist fungi in cropland soils across a 2,200 kms environmental gradient, including three bioclimatic regions (subtropical, warm temperate, and temperate). A few fungal taxa in our database were classified as generalist taxa (~1%). These generalists accounted for >35% of the relative abundance of all fungal populations, and most of them are Ascomycota and potentially pathotrophic. Compared to the specialist taxa (5–17% of all phylotypes in three regions), generalists had a higher degree of connectivity and were often identified as hub within the network. Structural equation modeling provided further evidence that after accounting for spatial and climatic/ edaphic factors, generalists had larger contributions to the fungal coexistence pattern than habitat specialists. Taken together, our study provided evidence that generalist taxa are crucial components for fungal community structure. The knowledge of generalists can provide important implication for understanding the ecological preference of fungal groups in cropland systems

Validating HY-2A CMR precipitable water vapor using ground-based and shipborne GNSS observations

The calibration microwave radiometer (CMR) on board the Haiyang-2A (HY-2A) satellite provides wet tropospheric delay correction for altimetry data, which can also contribute to the understanding of climate system and weather processes. The ground-based global navigation satellite system (GNSS) provides precise precipitable water vapor (PWV) with high temporal resolution and could be used for calibration and monitoring of the CMR data, and shipborne GNSS provides accurate PWV over open oceans, which can be directly compared with uncontaminated CMR data. In this study, the HY-2A CMR water vapor product is validated using ground-based GNSS observations of 100 International GNSS Service (IGS) stations along the global coastline and 56 d shipborne GNSS observations over the Indian Ocean. The processing strategy for GNSS data and CMR data is discussed in detail. Special efforts were made in the quality control and reconstruction of contaminated CMR data. The validation result shows that HY-2A CMR PWV agrees well with ground-based GNSS PWV with 2.67 mm as the root mean square (rms) within 100 km. Geographically, the rms is 1.12 mm in the polar region and 2.78 mm elsewhere. The PWV agreement between HY-2A and shipborne GNSS shows a significant correlation with the distance between the ship and the satellite footprint, with an rms of 1.57 mm for the distance threshold of 100 km. Ground-based GNSS and shipborne GNSS agree with HY-2A CMR well

Effects of bisphenol A exposure at different circadian time on hepatic lipid metabolism in mice

BackgroundLipid metabolism in liver shows circadian-dependent profiles. The hepatotoxicity of environmental chemicals is dependent on circadian time. ObjectiveTo observe the effects of bisphenol A (BPA) exposure at different zeitgeber time (ZT) on hepatic and blood lipid metabolism and decipher the underlying mechanisms related to circadian rhythm in mice. MethodsThirty-five female C57BL/6J mice were sacrificed every 4 h in a light-dark cycle (12 h/12 h). The liver tissues were collected to describe the circadian profiles of hepatic Rev-erba, Bmal1, Clock, Srebp1c, and Chrebp mRNA expression levels within 24 h. Thirty female mice were divided into 6 groups by the timing (ZT3 represents the 3 h after light on, ZT15 represents the 3 h after light off) and dose (50 or 500 μg·kg−1·d−1) of BPA exposure to observe hepatotoxicity. Mice were gavaged with designed doses of BPA once per day for 4 weeks. Mice were maintained with ad libitum access to food and water and measured body weight weekly. After the experiment, mice were euthanatized and liver tissues were separated to determine the biochemical indicators of lipid metabolism and lipid metabolism- and circadian-related gene mRNA expressions. ResultsHepatic Rev-erba, Bmal1, Clock, Srebp1c, and Chrebp mRNA expression levels were rhythmic during a 24 h period in mice. At ZT3 and ZT15, BPA did not alter body weight, plasma glucose, plasma total cholesterol, plasma low density lipoprotein cholesterol, and plasma triglycerides (P>0.05). The plasma high density lipoprotein cholesterol decreased in the 50 μg·kg−1·d−1 BPA group at ZT3 by 14.56% compared with the control group (P<0.05). The liver triglycerides increased in the 50 μg·kg−1·d−1 BPA group at ZT15 by 115.20% compared with the control group (P<0.05). BPA decreased Srebp1c mRNA expression level when dosing at ZT3 and increased Chrebp, Srebp1c, and Acc1 mRNA expression levels when dosing at ZT15 compared with the control group (P<0.05). BPA increased Bmal1 mRNA expression level and decreased Rev-erbα mRNA expression level at ZT3 exposure and decreased Bmal1 and increased Rev-erbα mRNA expression level at ZT15 exposure (P<0.05). ConclusionBPA exposure at light or dark period has different effects on hepatic lipid metabolism in mice. Hepatic lipid deposit appears when BPA is dosed at dark period. Rev-erbα-Bmal1 regulation circuits and the subsequent upregulation of Srebp1c and Chrebp and the target gene Acc1 may be involved

Criteria for determining the need for surgical treatment of tricuspid regurgitation during mitral valve replacement

<p>Abstract</p> <p>Background</p> <p>Tricuspid regurgitation (TR) is common in patients with mitral valve disease; however, there are no straightforward, rapidly determinably criteria available for deciding whether TR repair should be performed during mitral valve replacement. The aim of our retrospective study was to identify a simple and fast criterion for determining whether TR repair should be performed in patients undergoing mitral valve replacement.</p> <p>Methods</p> <p>We reviewed the records of patients who underwent mitral valve replacement with or without (control) TR repair (DeVega or Kay procedure) from January 2005 to December 2008. Preoperative and 2-year postoperative echocardiographic measurements included right ventricular and atrial diameter, interventricular septum size, TR severity, ejection fraction, and pulmonary artery pressure.</p> <p>Results</p> <p>A total of 89 patients were included (control, n = 50; DeVega, n = 27; Kay, n = 12). Demographic and clinical characteristics were similar between groups. Cardiac variables were similar between the DeVega and Kay groups. Right atrium and ventricular diameter and ejection fraction were significantly decreased postoperatively both in the control and operation (DeVega + Kay) group (<it>P </it>< 0.05). Pulmonary artery pressure was significantly decreased postoperatively in-operation groups (<it>P </it>< 0.05). Our findings indicate that surgical intervention for TR should be considered during mitral valve replacement if any of the following preoperative criteria are met: right atrial transverse diameter > 57 mm; right ventricular end-diastolic diameter > 55 mm; pulmonary artery pressure > 58 mmHg.</p> <p>Conclusions</p> <p>Our findings suggest echocardiography may be used as a rapid and simple means of determining which patients require TR repair during mitral valve replacement.</p

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Two ultraviolet radiation datasets that cover China

Ultraviolet (UV) radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization's measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes

Experimental Study on Quantitative Application of Electromagnetic Radiation Excited by Coal-rock Fracture

A coal-rock uniaxial compression experimental investigation was conducted in laboratory. Electromagnetic radiation (EMR) and acoustic emission (AE) signals were gained during coal-rock fracture under different antenna types and arrangements. The results show that EMR excited by coal-rock fracture are broadband frequency, the EMR and AE signals are from the same source, but their generation mechanism is different. Under the same frequency band of antenna, the EMR amplitude from antenna parallel with crack plane is bigger than from antenna vertical to crack plane. Thus, EMR signals from developing crack propagates along the crack surfaces, which are principle contributions to total EMR signals and the EMR signals from antenna reflect the crack state parallel with receiving direction plane of antenna in coal-rock under uniaxial compression. A quantitative relationship between EMR frequency along the major crack plane and crack was derived by previous studies, which can be used into applications for coal-rock dynamic disaster prediction in the future

Influence of thermomechanical processing on coarse particles, grain structure, and mechanical properties of Al–Cu alloy rings

Rings made of 2219 Al alloy are typically manufactured by multi-directional forging (MDF) and ring rolling at 460 °C, followed by heat treatment. However, this process often results in coarse elongated grains and a large number of coarse Al2Cu particles, resulting in rings with poor mechanical properties. As a strategy to refine the microstructure and improve the mechanical properties, a novel thermomechanical process was tested for ring manufacturing, with MDF at 510 °C and ring rolling at 240 °C. The results showed that use of MDF at higher temperatures resulted in increased spherical shapes and decreased numbers of coarse Al2Cu particles due to more complete dissolution. Decreasing the rolling temperature from 460 °C to 240 °C resulted in finer grain structure due to the increased nucleation ratio of static recrystallization during subsequent solution heat treatment. Samples prepared using this novel process exhibited fine equiaxed grains with sufficient dissolving of coarse Al2Cu particles, thus this method significantly improved the mechanical properties of the prepared material and decreased the anisotropy in three orthogonal directions