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Northern snakehead, Channa argus (C. argus), is an important economic and ecological fish species. The wild population of the species was sharply declined in the last decade. A high-quality reference genome could lay a solid foundation for the genetic and conservation studies for C. argus. In this work, we report a chromosomal genome assembly with PacBio and Hi-C technology using the albino northern snakehead, a color variety of C. argus. A 644.1-Mb genome with 24 chromosomes was obtained with a contig and scaffold N50 of 11.78 and 27.8 Mb, respectively. We inferred that C. argus diverged from A. testudineus around 85.6 million years ago. 514 expanded gene families and 214 positively selected genes were identified in the C. argus genome. The chromosome-level genome provides a valuable high-quality genomic resource for population, as well as genetic and evolutionary studies for C. argus and other species in Channidae.

Ocean tides in polar regions play an important role in the study of sea ice dynamics and floating ice shelves. The accuracy of existing ocean tide models in shallow waters and polar seas is much lower than that in open deep oceans. This study summarized the advances of state-of-the-art global tide models in the Antarctic Ocean, the construction of tide models around Circum-Antarctica, and five typical regions: Antarctic Peninsula, Ross Sea, Filchner–Ronne Ice Shelf (FRIS), Weddell Sea, and Amery Ice Shelf (AIS). The accuracy of FES 2014, TPXO9, EOT20, CATS 2008, and regional tide models in the Antarctic Ocean and typical areas was evaluated using tidal records and satellite altimetry data. EOT20 and ANTPEN04.01 models have higher accuracy in the Antarctic Peninsula, and the root sum square (RSS) values are 8.29 and 7.46 cm, respectively. TPXO9 has the highest accuracy in the Weddell Sea and FRIS and AIS and RSS values are 18.33 and 12.77 cm, respectively. TPXO9 and RIS_Optimal models have higher accuracy in the Ross Sea and Ross Ice Shelf (RIS), RSS values are 5.62 and 6.21 cm, respectively. The accuracy of FES 2014, TPXO9, CATS 2008, and the regional tide model in the Drake Passage, Kerguelen Islands, and Adelie–Mertz was evaluated using satellite altimetry data. The RSS values are less than 4 cm. By using the altimetry data at Sentinel-3A single-satellite crossovers in terms of the STD of the SLA, the comparison of the STDs show that FES2014 is the best.

This project aims to design a novel passive quasi-zero stiffness vibration isolator (QZS-VI) and analyze the static and dynamic mechanical properties of the QZS-VI. First, a novel combination of V-shaped lever, plate spring and cross-shaped structure (VL-PS-CS) vibration isolation platform is designed, and a nonlinear QZS-VI is built by parallel connecting VL-PS-CS and coil spring. Second, the static and dynamic modeling of QZS-VI are derived considering the geometrical nonlinearity of V-shaped lever and the large deflection of plate spring, and the average method is applied to obtain the displacement transmissibility. Third, the effects of different structural parameters (e.g., the lengths of long arm and short arm of V-shaped lever, the assembly angle between two arms, the thickness of plate spring) on the static mechanical and equivalent nonlinear friction properties of QZS-VI are thoroughly investigated. Finally, the vibration isolation performance of the designed QZS-VI is compared with another QZS-VI of buckled beam mechanism and traditional linear vibration isolator. The QZS-VI with VL-PS-CS fully explores the nonlinear advantages of plate spring and V-shaped lever and can achieve excellent high static and low dynamic stiffness and nonlinear friction properties. The superior static mechanical properties and nonlinear friction of QZS-VI can be tuned with different structural parameters. The designed QZS-VI exhibits much smaller resonant frequency, lower peak value and more stability property at the peak frequency than other isolators due to its special nonlinear friction and stiffness properties. The designed QZS-VI is practical, novel and suitable for low-frequency vibration isolation. The innovative structure provides novel insights into the design of passive vibration isolators and has great potential for application in engineering practice.

Iceberg detection is of great significance for marine environmental monitoring and safe sailing of vessels. It is an important part of the construction of the Arctic channel and the exploitation of the Arctic. Iceberg detection using synthetic aperture radar (SAR) images has unique advantages. Many machine learning algorithms can be used in the recognition of icebergs in SAR images. In order to maximize the performance of machine learning algorithms, it is necessary to evaluate different machine learning algorithms and their matching feature and feature standardization methods, so as to select the optimal iceberg detection process method. Therefore, based on Sentinel-1A SAR image, this paper uses a variety of machine learning methods, a variety of feature combinations and a variety of feature standardization methods for iceberg detection, and compares the performance differences of each process method. Machine learning algorithms include Bayes classifier (Bayes), back propagation neural network (BPNN), linear discriminant analysis (LDA), random forest (RF) and support vector machine (SVM); feature standardization methods include Min-max standardization, Z-score standardization and log function standardization; data sets are comprised of 969 iceberg and non-iceberg samples with 12 SAR image features, located mainly on the east coast of Greenland. The classification result is measured by the area under the receiver operating characteristic (ROC) curve (AUC). The results show that the AUC value of RF with the best configuration is the highest, reaching 0.945, which is 0.09 higher than worst Bayes. In terms of detection rate, under the case of 80% iceberg recall rate, the non-iceberg recall rate of RF is 92.6%, which is the best, 1.4% higher than the second BPNN, 2.6% higher than the worst Bayes; under the case of 90% iceberg recall rate, the non-iceberg recall rate of BPNN is 87.4%, 0.8% higher than the second RF and 2.7% higher than the worst Bayes. The above results show that it is very important to select the best machine learning algorithm, the best features and feature standardization method for iceberg detection.

Marine vertical datum system construction is the basic work of marine surveying. In the 2009-2012, China has preliminarily constructed the transformation and unification of different height/depth datum model in the China Sea of 80 nautical mile. In recent years, this model has been extended to the South China Sea, the western Pacific and the eastern Indian Ocean, and then a seamless vertical datum model in the south and north pole area to the whole world gradually will be constructed in the near future, this is the foundation of supporting the digital ocean construction in China. This paper mainly discusses the research status of marine vertical datum construction which had been carried out in major coastal countries or regions, analyzes the main work and approaches and key technologies in the process of the marine vertical datum system building, and then expounds the achievements and existing problems in the practice of our country marine vertical datum building.

My thesis includes three papers on contingent claims valuation of corporate securities using structural models of credit risk. Our study focuses on structural models and their applications in estimating damages in security class actions, option pricing and warrant pricing. Securities class actions typically involve some misrepresentation by a firm that overstates its true value. In securities class actions econometric models are used to assess damages to shareholders. However, studies on measuring damages for debt-holders are limited. My first paper uses a modified Merton framework to measure the impact of misrepresentation on the value of other components (e.g., debt, warrants) of a firm’s capital structure. Using structural models and leveraging the relationship between equity and firm value, we use observable eq- uity information to determine firm value and hence the effect of misrepresentation on value of other securities in the capital structure. We investigate various capital structures and show that misrepresentation can have a significant impact on the value of all components in the capital structure. We find that the misrepresentation impact on debt value depends on firm leverage and debt seniority and not on the warrant dilution factor. Generally, the debt for higher-leverage firms is more sensitive to the misrepresentation impact than for lower-leverage firms and junior debt is more affected by fraud than senior debt. The impact on warrant value is determined by warrant moneyness (stock price), with the dilution factor having no effect. My second paper extends the study in my first paper into the First Passage Time (FPT) framework, which is capable of modeling firms with complex debt structures. Our findings have important consequences for damages assessment and allocation of settlement awards in securities class actions. In some jurisdictions damages awarded are net of any hedge or risk- limitation transaction. Since corporate securities such as bonds and stocks are often held in portfolios for hedging purposes, measuring the effect of misrepresentation on all of the firm’s issuances is essential to accurately computed damages awards. In addition to our main findings, we explicitly discuss bankruptcy costs for the First Passage Time model. Furthermore, we are able to reduce a system of two non-linear equations, used to connect the unobservable firm value and firm value volatility to observable equity value and equity volatility, into one equation. This technique improves the ability to solve the non-linear system. My third paper studies option and warrant pricing under the structural framework (both Merton and FPT frameworks). We study the calibration of structural frameworks using a mar- ket implied volatility skew. We show that the model implied volatility skew under FPT frame- work is much more flexible than that under the Merton framework. Moreover, we extend the FPT structural framework to include warrants into the firm’s capital structure. Using historical market data, we show the pricing model (for both options and warrants) under FPT framework significantly outperforms the pricing models under Merton framework.

The situation of current research on power losses allocation in bilateral electricity markets is presented. Based on cooperative game theory, a novel nucleolus theory-based method for power losses allocation under the bilateral-transactions model is put forward and compared in detail with the Shapley-value-based allocation method. The impacts of different market players on network power losses are taken into account. With the new method, network power losses can be allocated to each transaction reasonably. The allocation results would not be affected by the sequence that each transaction is formed and be active. The method answers for the open, equal, and impartial principles of electricity market and can be easily understood and accepted by market players. Numerical tests validated the equity and validity of the method.

The technique of precise point positioning (PPP) is gradually becoming a popular method in GPS data-processing. In GPS observation equation, the unknown parameters can be separated into two parts: global parameters and local parameters. The global parameters include orbit, satellite clock and geodynamic parameters. The local parameters are site-occupation-spectific, such as position, tropospheric delay, etc. The formulas of local parameters are firstly derived under the network-solution and the PPP-solution conditions respectively. If the weight matrix of global parameters in PPP-solution is small enough, the cofactor matrices of local parameters are the same as that in network-solution. Then, 16 daily solutions are obtained in both PPP mode and network mode. Three sites are selected to compare the solutions. The experimental results demonstrated that the difference between two solutions in coordinates and tropospheric delays are only few millimeters. This level of difference can be neglected so that the ...

The multibeam sonars can provide hydrographic quality depth data as well as hold the potential to provide calibrated measurements of the seafloor acoustic backscattering strength. There has been much interest in utilizing backscatters and images from multibeam sonar for seabed type identification and most results are obtained. This paper has presented a focused review of several main methods and recent developments of seafloor classification utilizing multibeam sonar data or/and images. These are including the power spectral analysis methods, the texture analysis, traditional Bayesian classification theory and the most active neural network approaches.

Petrochemical studies indicate that the Yanghou metamorphic ultramafic rocks are composed of metamorphosed harzburgite and ultramafic cumulate. Trace element geochemistry and mineral chemistry of the metamorphic harzburgite indicate that they are relicts of depleted mantle. Systematic petrochemical, mineral chemical and geochronological studies led to such a conclusion that the Yanghou metamorphic ultramafic rocks may be the components of Late Sinian-Early Paleozoic ophiolites in South China.

This experiment was conducted to study the effect of dietary lipid level on the body index,lipid deposition and lipid metabolic enzyme activities of juvenile Onychostoma sima.We randomly assigned fish(n=900)with average initial body weight of(0.78±0.05)g into 6 groups consisting of 3 replicates that each replicate was 50 fish.Six isonitrogenous and isoenergetic diets(40% CP and 16.30 MJ/kg GE)were formulated containing 0(control group),2%,4%,6%,8%or 10% soybean oil respectively,Those actual lipid level was 2.83%,4.52%,6.68%,9.14%,11.35% and 14.07%,respectively.The experiment lasted for 60 days.The results showed that the condition factor(CF)of Onychostoma sima initially increased with increasing lipid levels,but then decreased,the CF was highest(2.64%)when the dietary lipid level was 9.14%,but there was no significant differences when lipid level were 6.68%-14.07%,(P0.05).The hepatosomatic index(HSI)increased with increasing dietary lipid levels(P0.05),while viscerosomatic index(VSI)had no significant differences(P0.05).The crude lipid content of muscle and liver were easily affected by dietary lipid levels,and the crude lipid content of muscle and liver increased with increasing dietary lipid levels.There was no significant effect of dietary lipid level on nitrogen gain(P0.05),energy gain was highest when the dietary lipid level was 14.07%,at the same time,the nitrogen and energy retention initially increased with increasing lipid levels,but then decreased,those were highest when the dietary lipid level was 11.35% and 9.14% respectively.Lipid gain of Onychostoma sima increased with increasing dietary lipid levels,but the lipid retention decreased(P0.05).The activities of intestinal lipase initially increased with increasing lipid levels,but then decreased,and the activities of lipoprotein lipase,hepatic lipase and total lipase first increased,then decreased as the level of dietary lipid increased,those were all highest(296.03 U/g,30.59 U/g,34.28 U/g and 64.87 U/g respectively)when the dietary lipid level was 9.14%.At the same time,fatty acid synthetetase(FAS)decreased with the increase of contents.Results of above show that suitable dietary lipid level could improve the utilization rate of feed nutrients and reduce body lipid deposition,but when dietary lipid level reaches or exceeds 11.35%,the lipid deposition in liver would increase,which is bad for health and growth of Onychostoma sima.

This experiment was conducted to study the effect of replacement of fish meal by soybean meal protein on the growth,body composition and hematology indices of juvenile Schizothorax prenanti.Healthy S.prenanti [with the initial weight(14.67±0.51) g]were randomly divided into six groups with three replicates of 30 fish.Six isonitrogenous and isoenergetic diets were formulated to contain different levels of soybean meal based upon the basal diet to replace fish meal protein 0(A1),20%(A2),40%(A3),60%(A4),80%(A5) and 100%(A6).The experiment lasted for 45 days.The results showed that the weight gain ratio(WGR),the specific growth ratio(SGR) and protein efficiency ratio(PER) were highest(118.08%,1.95%/d,207.22%,respectively),the feed conversion ratio(FCR) was the lowest(1.27) when the replace-ment ratio of fish meal protein by soybean meal was 60%(P0.05).The WGR,SGR,PER were signifi-cantly lower when the replacement ratio of fish meal protein of 100%,while the FCR was significantly higher than that of the other groups(P0.05).Based on quadratic regression analysis,the best replacement ratio of fish meal protein by soybean meal was 34.25% 45.46%.There were no significant difference in whole body moisture,crude ash and the condition factor(CF) with the replacement ratio of fish meal pro-tein by soybean meal increased,the crude protein in whole body was highest(15.53%) when the replace-ment ratio of fish meal protein by soybean meal was 60%.The crude protein and lipid in whole body had no significant difference when the replacement ratio of fish meal protein by soybean meal was less than 80%(P0.05).while the hepatopancreas somatic index(HIS) increased as soybean meal protein ratio in-creased,but there were no significant differences when the replacement ratio of fish meal protein by soy-bean meal was 0 80%(P0.05).Superoxide dismutase(SOD) activities have a certain fluctuation as soy-bean meal protein ratio increased,at the same time,SOD activities were highest when the replacement ratio of fish meal protein by soybean meal was 40%.Lysozyme(LSZ) activities were gradually increased when the replacement ratio of fish meal protein by soybean meal was 20% 60%(P0.05).The aspartate ami-notransferase(AST)and alanine aminotransferase(ALT)activities increased as soybean meal protein ratio increased,but there were no significant differences when the replacement ratio of fish meal protein by soybean meal was less than 80%(P0.05).The AST and ALT activities were significantly higher than the control group and other experimental groups(P0.05).Results of above show that a certain percentage soybean meal protein ratio in diet could promote the growth,and improve feed protein metabolism and immunity of S.prenanti.In conclusion,the maximum replacement ratio of fish meal protein by soybean meal was 80% in the diets of S.prenanti,and the most suitable replacement ratio of fish meal protein by soybean meal was 34.25% 45.46%.

Summarization: This work presents the first calibration results for the Jason-2 and the SARAL/AltiKa altimetric missions by using the permanent calibration facilities on the Qianli Yan islet (China). Qianli Yan is located in the Yellow Sea and only ∼3 km from the Jason-2 and SARAL/AltiKa crossover point. Analysis of the Jason-2 and SARAL/AltiKa waveform data and geophysical data over the Qianli Yan calibration area has proven that the altimeters and microwave radiometers are not contaminated by the mainland or the islet. The accuracies of the regional geoid model, provided by the First Institute of Oceanography (FIO), State Oceanic Administration of China, and the DTU10 MSS model were assessed by a GNSS buoy experiment. The results indicated that the FIO model is suitable for altimeter calibration in the Qianli Yan area. From the observations and the geoid model, the absolute biases for the Jason-2 and SARAL/AltiKa altimeters (2013–2014) were determined as 21.0 ± 5.9 and −44.0 ± 7.3 mm, respectively. The 2 years’ results indicated that the Jason-2 bias had no trend. However, the SARAL/AltiKa bias presented a downward trend that was more stable in 2014 than in 2013. The Qianli Yan results are consistent with those determined by other international dedicated calibration sites and crossover analysis. Presented on: Advances in Space Research

Summarization: In this work, absolute calibration of the Chinese HY-2 satellite altimetry mission is carried out, employing Pass No. 280 and the calibration facility, CRS1, located in the Southwest end of the island of Crete, Greece. Satellite Pass No. 280 is descending and follows a ground track almost parallel to the west coast of Crete. It comes close to the coast, at a distance of about 9 km from the CRS1 calibration site, and finally goes away south of Crete. The HY-2 sensor geophysical data records (S-GDR) have been incorporated into the calibration procedures and processing has taken place for cycles No. 54–62, at 20 Hz data rate. Some peculiarities in the HY-2 satellite altimeter data, as delivered and depicted in the I-GDR and S-GDR data, have also been noticed. All calibration results have been determined using a regional, precise and detailed geoid, along with a good knowledge of local ocean circulation and site characteristics and a well-defined sea-surface calibration methodology. The first preliminary results for the HY-2 altimeter calibration have shown that the initial cycles, up to No. 51, display an erratic behavior. After those cycles, the altimeter range bias values seem to be stable and reach a value of B = −45.6 cm ± 4.4 cm, when applying the net instrument corrections as provided in the GDR. If the relativistic effects of the satellite clocks are properly applied for the net instrument corrections, then the altimeter range bias goes down to B = −27 cm ± 3 cm. Also, preliminary cross-over analysis with the SARAL/AliKa and Jason-2 satellites show a bias of B = −23 cm, and B = −28.5 cm, respectively. The performance of the HY-2 on-board radiometer has also been examined in terms of the wet troposphere corrections and shows a mean difference of −1 cm ± 0.1 cm with respect to in-situ GNSS-derived corrections. Finally, the ionosphere path corrections of the HY-2 satellite show a difference of +1 cm ± 1.1 cm, when compared against the GNSS-derived ionosphere values Presented on: Advances in Space Research