大穗型杂交水稻父本材料的耐冷性筛选与鉴定

冷害已成为我国杂交水稻发展中影响安全生产的一大问题,而与超级杂交稻密切关联的大穗型水稻的耐冷性鉴定尚没有成型的方法。以21个现有杂交稻水稻大穗型父本品种（品系）为材料,在水稻花粉母细胞减数分裂期采用人工气候室模拟当地水稻典型受害气象条件,进行连续7d低温处理（日平均温度175℃）,以受精率和毎穗颖花数为联合筛选指标进行了低温耐性筛选试验。结果表明,根据各品种对低温的反应,可将其分为4种类型,分别为耐低温型、较耐低温型、较感低温型和低温敏感型。其中BL006、R HQ和香八等3品种属于耐低温型,C 418属于低温敏可感型。经在水稻花粉母细胞减数分裂期低温处理后,耐低温型品种BL006、R HQ和香八的颖花受精率和毎穗颖花数受影响较小,花药长度变化不大,每柱头花粉总数、花粉萌发数和花粉萌发率降幅小;相反,低温敏感型品种C 418受精率和每穗颖花数严重下降,花药长度大幅减小,每柱头花粉总数、花粉萌发数和花粉萌发率显著降低。由此证明,针对大穗型水稻品种的耐冷性鉴定,采用颖花受精率和每穗颖花数作为联合筛选指标的人工气候室模拟鉴定法可能是一种可行的方法     

不同温度下异波折板反应器处理生活污水的研究

本实验采用64．8L的厌氧异波折流板反应器处理生活污水,研究了低温对异波折流板反应器运行效能的影响。结果表明,温度从30℃降至20℃反应器运行15d达到稳定后,COD去除率仅从83．6％T降至76．9％。各隔室的VFA浓度均有所上升,前面隔室升幅较大,比甲烷活性略有下降;当温度从20℃下降至10℃时,产氢产乙酸茵和产甲烷菌等受到较大影响,在反应器运行达到稳定后COD去除率从76．9％T降至45％-55％,出水水质受影响较大,比甲烷活性下降幅度较大。     

SPD与后备保护断路器配合性能研究

目前使用的后备保护断路器,由于不能与电涌保护器(SPD)协调配合,当电源异常或SPD劣化失效时,常导致火灾、设备遭雷击损坏事故的发生,针对这种情况,运用8/20μs、10/350μs波形模拟雷电流对多种型号后备保护器进行冲击试验测试和分断工频能力研究,对试验结果进行分析。结果表明,断路器不能限制瞬态过电压,且SPD短路失效时不能快速分断工频电流,应以SPD专用断路器取而代之。简要介绍了新型SPD专用断路器的原理,并对其性能进行了验证。     

A practical application of Driscoll's equation for predicting the acid-neutralizing capacity in acidic natural waters equilibria with the mineral phase gibbsite

A practical application of Driscoll's equation for predicting the acid-neutralizing capacity (ANC) in acidic waters equilibria with the mineral phase gibbsite is reported in this paper. Theoretical predication values of ANC are compared with the experimental data obtained from different literatures. The effect of aluminum (Al) on the value of ANC is investigated. It indicates that Al plays an important role in regulating the buffering effects in acidic natural waters. Failure to consider Al in acidic waters may bias assessment results in certain situations so as to overestimate the ANC values in response to increase in atmospheric deposition.     

Dynamics of aluminum speciation in forest-well drainage waters from the Rhode River watershed, Maryland

This paper reports an investigation of the dynamics of aluminum (Al) speciation in the forest-well waters from study site 110 of the Rhode River watershed, a representative sub-unit of Chesapeake Bay. Seasonal changes of Al speciation are evaluated by a modified MINEQL computer model using chemical equilibrium calculation. It was found that Al-F and Al-Org complexes were the dominate forms, whereas toxic forms of Al3+ and Al-OH were not significant. This indicates that Al toxicity is not very serious in the Rhode River area due to the high concentrations of fluoride and organic materials, even though sometimes pH is very low (approximately 4). Increased H+ or some other associated factors may be responsible for the decline in fish and amphibian population on the watershed.     

Polybrominated diphenyl ethers in South China maternal and fetal blood and breast milk

Twenty-one-paired human fetal and maternal serum and 27 breast milk samples at South China were analyzed for concentrations of polybrominated diphenyl ethers (PBDEs). Seven PBDE congeners (BDE-28, -47, -99, -100, -153, -154, and -183) were quantified using gas chromatography/mass spectrometry (GC/MS). This is the first report to present the residue levels of PBDEs in human samples of China. The concentrations of total PBDEs ranged from 1.5 to 17 ng/g in the samples and were within the range reported in European samples for a similar population, but lower than human tissue levels in North America. BDE-47 and -153 were the dominant PBDE congeners in all samples and accounted for 60% of the total PBDEs. Further research is needed to determine the exposure route of PBDEs and their health effects.     

Environmental factors and spatiotemporal distribution characteristics of the global outbreaks of the highly pathogenic avian influenza H5N1

The spread of highly pathogenic avian influenza H5N1 has posed a major threat to global public health. Understanding the spatiotemporal outbreak characteristics and environmental factors of H5N1 outbreaks is of great significance for the establishment of effective prevention and control systems. The time and location of H5N1 outbreaks in poultry and wild birds officially confirmed by the World Organization for Animal Health from 2005 to 2019 were collected. Spatial autocorrelation analysis and multidistance spatial agglomeration analysis methods were used to analyze the global outbreak sites of H5N1. Combined with remote sensing data, the correlation between H5N1 outbreaks and environmental factors was analyzed using binary logistic regression methods. We analyzed the correlation between the H5N1 outbreak and environmental factors and finally made a risk prediction for the global H5N1 outbreaks. The results show that the peak of the H5N1 outbreaks occurs in winter and spring. H5N1 outbreaks exhibit aggregation, and a weak aggregation phenomenon is noted on the scale close to 5000 km. Water distance, road distance, railway distance, wind speed, leaf area index (LAI), and specific humidity were protective factors for the outbreak of H5N1, and the odds ratio (OR) were 0.985, 0.989, 0.995, 0.717, 0.832, and 0.935, respectively. Temperature was a risk factor with an OR of 1.073. The significance of these ORs was greater than 95%. The global risk prediction map was obtained. Given that the novel coronavirus (COVID-19) is spreading globally, the methods and results of this study can provide a reference for studying the spread of COVID-19.

     

Spatiotemporal development of land use systems,influences and climate variability in Southwestern Ghana (1970–2020)

Environment, Development and Sustainability - This study assesses the spatiotemporal development of land use systems and climate variability in Southwestern Ghana over the past five decades using...     

High-expression and characterization of a novel serine protease from Ornithinibacillus caprae L9T with eco-friendly applications

Environmental Science and Pollution Research - In the current work, a novel thermophilic serine protease gene (P3862) from Ornithinibacillus caprae L9T was functionally expressed in Bacillus...     

Arbuscular mycorrhizal colonization increases plant above-belowground feedback in a northwest Chinese coal mining–degraded soil by increasing photosynthetic carbon assimilation and allocation to maize

Environmental Science and Pollution Research - A three-compartment culture system was used to study the mechanism by which the AM fungus Funneliformis mosseae influences host plant growth and soil...