Diatom-based dissolved inorganic nitrogen reconstruction in the Changjiang River estuary and its adjacent areas

A five-component weighted average partial least squares(WA-PLS)calibration model was developed by analysing diatom assemblages in 34 surface sediment samples(collected in 2015)from the Changjiang River estuary(CRE)and its adjacent areas to infer dissolved inorganic nitrogen(DIN)concentrations.Eighteen additional sets of surface sediment diatoms and corresponding upper water DIN data(collected in 2012)were used to evaluate the accuracy of the model,and the relationship between observed and diatom-inferred DIN(DI-DIN)values(R2=0.85)illustrated the strong performance of the transfer function,indicating that precise reconstructions of former DIN are possible.The diatom-DIN transfer function was applied to the diatom record from a sediment core DH8-2(1962‒2012)collected in the Fujian-Zhejiang area south of the CRE.The reconstruction based on the DI-DIN model showed a significant DIN increase from 1962-2012,reflecting the influence of human activities on the very large increase in eutrophication.Three distinct periods can be seen from the changes in DIN and diatom taxa.In the 1962-1972 period,the DIN content was relatively low,with an average of 5.94μmol/L,and more than 80%of the diatom species identified were benthic taxa.In the 1972-2004 period,as the impact of human activities intensified,large nutrient inputs caused the DIN content to increase,with an average of 8.25μmol/L.The nutrient inputs also caused a significant change in the nutrient components and a distinct increase in small planktonic taxa.In the 2004-2012 period,the DIN content continued to rise,fluctuating at approximately 10μmol/L.A continuous increase in the frequency of planktonic taxa(up to 65.48%)indicated that eutrophication was further intensified,which was confirmed by the transformation from diatom-induced red tide to dinoflagellate-induced red tide during this period.

A Novel Protection and Utilization Pattern for Urban Wetland—As an Example of Hemu Wetland in Hangzhou, China

This paper proposes an innovative plan and its implement strategy of Hemu urban wetland. The plan takes into consideration its historical background and current status, its protection significance, strategies, solutions and support conditions. It highlights the landscape characteristics of rivers and lakes, and restores its historical flood prevention functions and climate regulation for the city. Especially, this paper proposes to achieve the restoration of “Mulberry-sided Fish Pond” farming style—an important agricultural heritage created by the ancestors inside the wetland, which is a unique and creative way to use low land for ecological agriculture and cycling economy. The proposed wetland sewage treatment schemes would be of practical importance to improve and enhance the ecological environment and promote the construction of ecological civilization in the region. The “Two zones—One block and Three complexes” protection and utilization plan is reasonable and feasible. It fully presents the functions of the wetland for its production, living, life forms and ecology, and is characterized by joint protection of the wetland by original residents and social public. This will result in active, instead of passive, wetland protection, like turning a “blood transfusion protection” to “hematopoietic protection”, which reflects the sustainable development. The paper offers valuable information and strategies for planning and development of urban wetland.

Clay surface modification and its coagulation of red tide organisms

Surface modification of montmorillonite by means of Mg2+ insertion reaction has been studied and a positively charged montmorillonite has been prepared. The effects of preparation temperature and Mg2+ concentration on the positive charge property of the clay and on the clay coagulating Heterosigma akashiwo have been studied. The results showed that the modified clay enhanced the coagulation and the used amount decreased to 1/5—1/10 of the original. The removal rates of Heterosigma akashiwo were correlated positively with positive charge on the clay in accordance with theoretical model.

Effects of ammonium and nitrate on encystment and growth of Scrippsiella trochoidea

To avoid unfavorable environmental conditions, Scrippsiella trochoidea is capable of forming a resting cyst in the process of growth. In the present study,we investigated the effects of nitrate and ammonium on the growth and encystment of S. trochoidea. We incubated S.trochoidea in modified f/2 media without nitrogen and silicate in flasks. The flasks were divided into two groups.Nitrate was added as a nitrogen source in the first group,and ammonium was added in the second group. The concentrations of the nitrogen compounds were 0, 10, 30, 60,and 90 lmol/L. The results indicate that NO3--N favors cell growth, and the cultures with a higher concentration of NO3--N were ineffective at forming cysts. In contrast,NH4--N promoted cell growth and cyst formation. At similar concentrations as NO3--N, NH4--N had a toxic effect on cell growth and increased the cyst formation ratio.Thus, the NH4--N concentration is an important factor for controlling encystment. We believe that the impact of NH4--N in inducing cyst formation may be a useful feedback mechanism in ecological systems.

Effect of Different Reinforcing Fillers on Properties,Interfacial Compatibility and Weatherability of Wood-plastic Composites

Utilization of biochar in plastic based blends offers a sustainable way to renewable materials as well as value-added use of wood waste.To investigate the interfacial compatibility and weatherability properties of biochar composites,four types of Wood-Plastic Composites(WPC)were prepared by an extrusion process.The mechanical properties,water absorptions,thermal and viscoelastic properties,and rheological behavior of the composites were also evaluated.The decolorizing carbon(NA)composite melts showed the higher modulus and viscosity,indicating better melt strength.The NA composites performed the best in tensile properties(strength of 2&6 MPa and modulus of 3.4 GPa)and had strong interfacial interaction between particles and the matrix.The degree of HDPE crystallinity in the biochar and carbon composites decreased relative to Douglas-fir(DF)composites,while the thermal properties of the composites improved compared with DF composites.For the water resistance,the DF composites displayed the highest water absorption(3.7%)and thickness swell(2.9%).During accelerated weathering tests,longer exposure time increased the color change and lightness,especially for DF composite.NA and biochar composites resulted in improved photostability.This study opens up a pathway to utilize effectively the renewable biochar as reinforcing filler in WPC in outdoor applications.

Prediction of pilot workload in helicopter landing after one engine failure

This paper presents a method to predict the pilot workload in helicopter landing after one engine failure.The landing procedure is simulated numerically via applying nonlinear optimal control method in the form of performance index,path constraints and boundary conditions based on an augmented six-degree-of-freedom rigid-body flight dynamics model,solved by collocation and numerical optimization method.UH-60 A helicopter is taken as the sample for the demonstration of landing after one engine failure.The numerical simulation was conducted to find the trajectory of helicopter and the controls from pilot for landing after one engine failure with different performance index considering the factor of pilot workload.The reasonable performance index and corresponding landing trajectory and controls are obtained by making a comparison with those from the flight test data.Furthermore,the pilot workload is evaluated based on wavelet transform analysis of the pilot control activities.The workloads of pilot control activities for collective control,longitudinal and lateral cyclic controls and pedal control during the helicopter landing after one engine failure are examined and compared with those of flight test.The results show that when the performance index considers the factor of pilot workload properly,the characteristics of amplitudes and constituent frequencies of pilot control inputs in the optimal solution are consistent with those of the pilot control inputs in the flight test.Therefore,the proposed method provides a tool of predicting the pilot workload in helicopter landing after one engine failure.

Multigene editing via CRISPR/Cas9 guided by a single-sgRNA seed in Arabidopsis

We report that a solo single-guide RNA （sgRNA） seed is capable of guiding Clustered Regularly Interspaced Short Palindromic Repeats （CRISPR）/CRISPR -associated 9 （CRISRP/Casg） to simultaneously edit multiple genes AtRPL10A, AtRPL10B and AtRPL10C in Arabidopsis. Our results also demonstrate that it is possible to use CRISPR/Cas9 technology to create AtRPLlo triple mutants which otherwise cannot be generated by conventional genetic crossing. Compared to other conventional multiplex CRISPR/Cas systems, a single sgRNA seed has the advantage of reducing off-target gene-editing. Such a gene editing system might be also applicable to modify other homologous genes, or even less-homologous sequences for multiple gene-editing in plants and other organisms.

Comparative WGBS identifies genes that influence non-ripe phenotype in tomato epimutant Colourless non-ripening

Whole-genome bisulfite sequencing(WGBS)allows single-base resolution and genome-wide profiling of DNA methylation in plants and animals.This technology provides a powerful tool to identify genes that are potentially controlled by dynamic changes of DNA methylation and demethylation.However,naturally occurring epimutants are rare and genes under epigenetic regulation as well as their biological relevances are often difficult to define.In tomato,fruit development and ripening are a complex process that involves epigenetic control.We have taken the advantage of the tomato epimutant Colourless non-ripening(Cnr)and performed comparative mining of the WGBS datasets for the Cnr and Sl CMT3-silenced Cnr fruits.We compared DNA methylation profiles for the promoter sequences of approximately 5,000 bp immediately upstream of the coding region of a list of20 genes.Differentially methylated regions were found for some of these genes.Virus-induced gene silencing(VIGS)of differentially methylated gene Sl DET1 or Sl PDS resulted in unusual brown pigmentation in Cnr fruits.These results suggest that comparative WGBS coupled with VIGS can be used to identify genes that may contribute to the colourless unripe phenotype of fruit in the Cnr epimutant.

CO2 corrosion behaviors of 13Cr steel in the high-temperature steam environment

The study aims to explore the corrosion behaviors of 13Cr steel in the high-temperature steam environment.The corrosion behaviors of 13Cr steel were tested in CO2 auxiliary steam drive environment simulated with the HTHP autoclave.The corrosion morphology and product composition were explored by SEM,EDS,XRD and XPS.The exploration results showed the corrosion rate of 13Cr steel in the high-temperature steam environment was less than 0.04 mm/a.The corrosion behaviors of 13Cr steel were mainly affected by temperature and chloride ion concentration.Temperature inhibited steam condensation and the compactness of Cr-rich layer.With the increase in temperature,more droplets were adsorbed on the surface of 13Cr steel and the compactness of the Crrich layer is worse.Chloride ions affects the activity of Fe atoms in the metal matrix.When chloride concentration increased,Fe^2+concentration in the solution and FeCO3 content in the rich-Cr layer were increased and the rich-Cr layer became looser.

Profiles of and variations in aluminum species in PAC-MC used for the removal of blooming microalgae

Polyaluminum chloride modified clay(PAC-MC)is a safe and efficient red tide control agent that has been studied and applied worldwide.Although it is well known that the distribution of hydrolytic aluminum species in PAC affects its flocculation,little is known about the influence of particulars aluminum species on the microalgae removal efficiency of PAC-MC;this lack of knowledge creates a bottleneck in the development of more efficient MCs based on aluminum salts.The ferron method was used in this study to quantitatively analyze the distributions of and variations in different hydrolytic aluminum species during the process of microalgae removal by PAC-MC.The results showed that Ala,which made up 5%–20%of the total aluminum,and Alp,which made up 15%–55%of the total aluminum,significantly affected microalgae removal,with Pearson’s correlation coefficients of 0.83 and 0.89,respectively.Most of the aluminum in the PAC-MC sank rapidly into the sediments,but the rate and velocity of settlement were affected by the dose of modified clay.The optimal dose of PAC-MC for precipitating microalgae was determined based on its aluminum profile.These results provide guidance for the precise application of PAC-MC in the control of harmful algal blooms.

Regeneration and utilization of nutrients during collapse of a Mesodinium rubrum red tide and its influence on phytoplankton species composition

High-biomass red tides occur frequently in some semi-enclosed bays of Hong Kong where ambient nutrients are not high enough to support such a high phytoplankton biomass. These high-biomass red tides release massive inorganic nutrients into local waters during their collapse. We hypothesized that the massive inorganic nutrients released from the collapse of red tides would fuel growth of other phytoplankton species. This could influence phytoplankton species composition. We tested the hypothesis using a red tide event caused by Mesodinium rubrum(M. rubrum) in a semi-enclosed bay, Port Shelter. The red tide patch had a cell density as high as 5.0×10~5 cells L^(-1), and high chlorophyll a(63.71 μg L^(-1)). Ambient inorganic nutrients(nitrate:NO_3^-, ammonium: NH_4^+, phosphate: PO_4^(3-), silicate: SiO_4^(3-)) were low both in the red tide patch and the non-red-tide patch(clear waters outside the red tide patch). Nutrient addition experiments were conducted by adding all the inorganic nutrients to water samples from the two patches followed by incubation for 9 days. The results showed that the addition of inorganic nutrients did not sustain high M. rubrum cell density, which collapsed after day 1, and did not drive M. rubrum in the non-red-tide patch sample to the same high-cell density in the red tide patch sample. This confirmed that nutrients were not the driving factor for the formation of this red tide event, or for its collapse. The death of M. rubrum after day 1 released high concentrations of NO_3^-,PO_4^(3-), SiO_4^(3-), NH_4^+, and urea. Bacterial abundance and heterotrophic activity increased, reaching the highest on day 3 or 4, and decreased as cell density of M. rubrum declined. The released nutrients stimulated growth of diatoms, such as Chaetoceros affinis var. circinalis, Thalassiothrix frauenfeldii, and Nitzschia sp., particularly with additions of SiO_4^(3-) treatments, and other species. These results demonstrated that initiation of M. rubrum red tides in the bay was not directly driven by nutrients.However, the massive inorganic nutrients released from the collapse of the red tide could induce a second bloom in low-ambient nutrient water, influencing phytoplankton species composition.

Programmed cell death induced by modified clay in controlling Prorocentrum donghaiense bloom

Modified clay(MC),an effective material used for the emergency elimination of algal blooms,can rapidly reduce the biomass of harmful algal blooms(HABs)via flocculation.After that,MC can still control bloom population through indirect effects such as oxidative stress,whichwas initially proposed to be related to programmedcell death(PCD)at molecular level.To further study theMC induced cell death in residual bloom organisms,especially identifying PCD process,we studied the physiological state of the residual Prorocentrum donghaiense.The experimental results showed that flocculation changed the physiological state of the residual cells,as evidenced by growth inhibition and increased reactive oxygen species production.Moreover,this research provides biochemical and ultrastructural evidence showing that MC induces PCD in P.donghaiense.Nuclear changes were observed,and increased caspase-like activity,externalization of phosphatidylserine and DNA fragmentation were detected in MC-treated groups and quantified.And the mitochondrial apoptosis pathway was activated in both MC-treated groups.Besides,the features of MC-induced PCD in a unicellular organism were summarized and its concentration dependent manner was proved.All our preliminary results elucidate the mechanism through which MC can further control HABs by inducing PCD and suggest a promising application of PCD in bloom control.

监狱企业依法履行职能的问题及对策——从完善《中华人民共和国监狱法》的视角

中国监狱在改造罪犯过程中,通过党的政策和国家法律法规保障,坚持灵活多样的手段方式,不断提升工作质效。监狱企业作为劳动改造的具体承担者,发挥了“将罪犯改造成为守法公民”重要支撑作用。在全面依法治国背景下,全面认识新时代监狱企业及其职能特点,深度剖析其在职能履行中的法定地位不明确、组织不顺畅、边界不清晰、监督不到位等问题,着力以法治思维和法治方式强化制度供给,探索在《中华人民共和国监狱法》中设立“监狱企业”专章,明确监狱企业的性质、职能、组织管理等,标定履职边界,消除履职障碍,化解职能扩展的风险,将有利于促进其沿着“为改造罪犯服务”职能方向依法规范运行。

Influence of thermal oxidation on as-synthesized detonation nanodiamond

The thermal property of an as-synthesized black powder, a detonation nanodiamond （DND） product, was first analyzed, followed by thermal oxidation to modify its surface. During the thermal treatment, the non-diamond carbonaceous shell of the black powder was oxidized, with the likelihood of forming a C-O-C bonding between carbon atoms on the particle surface. This new structure may rupture with intensified oxidation through increasing the heating temperature and prolonging the process duration. As more oxygen-containing functional groups form on the particle surface, the particle surface becomes negatively charged, and the powder turns to be more hydrophilic.

依法纠正狱内罪犯冤错案件探析

狱内罪犯中的冤错案件势必影响正常的监管改造秩序和公正执法的社会效益。依法纠正狱内冤错案件是体现监狱现代治理能力、文明执法水平和执法公信力的重要标识。监狱在依法惩罚和改造罪犯过程中,坚守以人民为中心的发展理念,站在化解社会矛盾风险的高度主动作为,联动法院、检察院等政法机关,勠力推动狱内冤错案件得到依法及时纠正,努力让人民群众在每一个执法活动中真切感受到公平正义,当是凸显监狱价值坚守和文明执法的时代选择。