Diversity of microbial plankton across the Three Gorges Dam of the Yangtze River,China

The Three Gorges Dam （TGD） of the Yangtze River, China, is one of the largest irrigation and hydroelectric engineering projects in the world. The effects of huge man-made projects like TGD on fauna and macrophyte are obvious, mainly through changes of water dynamics and flow pattern; however, it is less clear how microorganisms respond to such changes. This research was aimed to examine differences in microbial diversity at different seasons and locations （in front of and behind the TGD）. In addition, differences between particle-attached and free-living communities were also examined. The community structures of total and potentially active microorganisms in the water columns behind and in front of the TGD were analyzed with the DNA- and RNA-based 16S rRNA gene phylogenetic approaches over three different seasons. Clone libraries of 16S rRNA genes were prepared after ampli- fication from extracted DNA and, for some samples, after preparing cDNA from extracted rRNA. Differ- ences were observed between sites at different seasons and between free-living and particle-attached communities. Both bacterial and archaeal communities were more diverse in summer than in winter, due to higher nutrient levels and warmer temperature in summer than in winter. Particle-attached micro- organisms were more diverse than free-living communities, possibly because of higher nutrient levels and heterogeneous geochemical micro-environments in particles. Spatial variations in bacterial community structure were observed, i.e., the water reservoir behind the TGD （upstream） hosted more diverse bacte- rial populations than in front of the dam （downstream）, because of diverse sources of sediments and waters from upstream to the reservoir. These results have important implications for our understanding of responses of microbial communities to environmental changes in river ecosystems affected by dam construction.

植物生长调节剂对4年树龄澳洲坚果品HASE695果实发育的影响

【目的】探究不同浓度下的几种植生长调节剂对HASE695果实发育的影响,确定植物生长调节剂合理施用浓度,为澳洲坚果优质丰产栽培技术提供借鉴。【方法】以4年树龄HASE695为试验对象,选取GA3、BR和CPPU等植物生调节剂为保果剂,设置了12个不同的处理浓度。比较了不同处理对鲜果横径、鲜果纵径、鲜果重、果皮厚、鲜种重、种横径、种纵径、果形指数、单株产量等果实发育参数指标的差异。【结果】GA320 mg/L处理对果横径、果纵径、鲜果重、鲜种重等指标影响明显,分别比对照增加16.53%、17.01%、46.14%、26.82%;GA340 mg/L处理对单株产量增产效果较好,达13.33 kg,产量增加44.7%;BR 0.06 mg/L处理对鲜果纵径、鲜果重、果皮厚、鲜种重、种横径、种纵径等指标作用明显,分别增加13.9%、56.1%、29.81%、40.39%、14.82%、12.19%。BR 0.4 mg/L处理果形指数提升10.38%,单株产量达16.33 kg,增产效果好,产量增加77.3%;CPPU 20 mg/L处理对鲜果横径、鲜果纵径、鲜果重、果皮厚、鲜种重和种纵径等参数影响明显,分别增加13.66%、11.14%、37.21%、21.45%、19.05%、5.56%。CPPU 40 mg/L处理对鲜果横径和果形指数提升10.69%、3.89%、单株产量达17.76kg,增产效果好,产量增加92.83%;20mg/L GA3+0.13 mg/L LBR+20 mg/L CPPU混合处理对鲜果横径、鲜果纵径、鲜果重、鲜种重、种横径和种纵径等参数影响明显,分别增加18.06%、14.61%、54.58%、33.99%、12.9%、12.79%。40 mg/L GA3+0.4 mg/L BR+40 mg/L CPPU混合处理增产效果最好,单株产量达18.07 kg,产量增加96.19%。【结论】花谢后1~7天内,喷施GA3、BR、CPPU均能提高澳洲坚果产量和改善品质,其中40 mg/L GA3+0.4 mg/L BR+40 mg/L CPPU混合处理单株产量达18.07 kg,产量增加96.19%,增产效果较好,是较为适宜的组合配比。

乡村振兴背景下休闲农业经营与管理专业校企合作人才培养模式研究

休闲农业经营与管理专业是乡村振兴背景下新兴的专业,其符合我国现代农业的发展需求,是实现现代化农业强国目标的重要途径。校企合作为一种有效的育人模式,对培养休闲农业经营与管理专业应用型创新人才发挥重要功能。如何加强校企合作人才培养是当前专业和企业需要共同面临的挑战。文章将分析当前校企合作的内涵,当前休闲农业经营与管理专业校企合作存在的问题,并根据不足之处针对性地提出解决建议,旨在为为我国涉农高校休闲农业经营与管理农业校企合作人才培养提供参考,为培养新型高素质应用型创新人才提供启示和借鉴。

Comparing the Seedling Growth of Six Precious Species in Southern China

Seedling stage is an important period for forestry.The aim of this study was to estimate the growth trend of six local precious species and consider their implications for silviculture on forestry.We assessed height,diameter near ground and crown width at 1,4,6 and 8-month.The variance analysis indicated that there were significant differences between species on all traits except diameter near ground and crown width at 8-month.There were no significant differences on height and crown width at all ages among replicates whereas there were significant differences on diameter near ground at 1 and 4 months,differences on diameter near ground at 6 months and no difference on diameter near ground at 8-month.The significant differences among interaction of species and replicates on diameter near ground at 1-months,4-month,6-month and crown width at 8-month were also found.Dalbergia odorifera had a higher growth period after 6-month.Aquilaria sinensis(Lour.)Spreng,Swietenia mahagoni(L.)Jacq.,Hopea hainanensis Merr.et Chun,Homalium hainanense Gagnep.and Cassia siamea Lam.had the same growth trend on all traits at the whole time.

Eucalypts in China:Research History,Present Situation and Future Prospect

Silviculture is the major procedures in forest research.Silviculture is traditionally focused on various aspects of tree planting,such as tree selection,site preparation,irrigation and fertilization and so on,and the role of silviculture at that time is to manage forests scientifically for continuous production of goods and services while meeting biological and economic requirements.During the past three decades,an increase in research on silviculture has improved Eucalyptus productivity and on wood properties.But,very little information about this procedure on the review of Eucalyptus grown in China has been published even though this species was introduced many years.This paper reviews the available information regarding research history and progress of silviculture under Chinese ecological conditions and to outline some suggestions to them.

Effects of Cooking Temperature and Storage Time on the Quality of Macadamia Nut Oil

The purpose is to study the influence of cooking and storage habits on the quality of macadamia nut oil,so as to provide reference for macadamia nut processingenterprises and consumers.Macadamia oil was treated at 100℃,200℃,300℃,microwave heating,45℃constant temperature storage,natural light for different times,and its acid value,peroxide value,squalene,sterol and fatty acid content were detected according to the national standard method.The results showed that the acid value and peroxide value increased with time.The acid value and peroxide value of macadamia oil cooked at 300℃and stored under natural light were higher than those heated by microwave and stored at 45℃,and increased rapidly with the increase of cooking and light time.The acid value was as high as 0.77 mg/g,with an increase of 63.8%,and the peroxide value was as high as 6.18 mg/g,with an increase of 43.7%.As for squalene,it decreased in varying degrees with heating time and storage time.Squalene in macadamia oil cooked at 300℃and stored under natural light were lower than those heated by microwave and stored at 45℃constant temperature,respectively,and decreased rapidly with the increase of cooking and light time,with the reduction ranges of 38.6%and28.4%respectively;Stigmasterol was not detected in macadamia oil.But in macadamia oil the content ofβ-sitosterol was 0.132 g/100 g,and the content did not change significantly in each treatmentgroup.In the experimental treatment group,the content of fatty acids in macadamia oil had different trends.After treatment at 300℃for 20 minutes,the content of oleic acid decreased by 75.66%,the content of palmitic acid decreased by 75.28%,and thecontent of palmitic acid decreased by 74.12%.In conclusion,low temperature heating,microwave heating and storage away from light can better preserve the quality of macadamia oil,this study will provide a theoretical basisfor the rational utilization of macadamia oil as cooking oil.

Plasticity in Metamorphic Traits of Rice Field Frog(Rana limnocharis) Tadpoles:The Interactive Effects of Rearing Temperature and Food Level

In organisms with complex life cycles, such as amphibians, morphological variation is strongly influenced by environmental factors （e.g. temperature） and maternal effects （e.g. diet）. Although temperature and food level exert a strong influence on larval growth, little is known about the interacting effects of these factors on age and size at metamorphosis. In this study, plasticity in growth rates, survival, larval period, and size at metamorphosis were examined in Rice field Frog （Rana limnocharis） under different combinations of rearing temperature and food level. Rearing temperature did not affect age at metamorphosis, but a significant interaction between temperature and food level revealed that of tadpoles feeding at a high food level, those reared at 32℃ had a shorter length of larval period than those reared at 29℃ or 26℃. Similarly, our results also showed high food level produced a larger growth rate and mass at metamorphosis at 32℃, but not at 29 and 26℃. Therefore, our results revealed that the effects of food level on larval growth and metamorphosis were highly dependent on developmental temperature.

A nomogram for predicting acute respiratory distress syndrome in COVID-19 patients

Objective: To predict the in-hospital incidence of acute respiratory distress syndrome(ARDS) in COVID-19 patients by developing a predictive nomogram.Methods: Patients with COVID-19 admitted to Changsha Public Health Centre between 30 January 2020, and 22 February 2020 were enrolled in this study. Clinical characteristics and laboratory variables were analyzed and compared between patients with or without ARDS. Clinical characteristics and laboratory variables that were risk factors of ARDS were screened by the least absolute shrinkage and selection operator binary logistic regression. Based on risk factors, a prediction model was established by logistic regression and the final nomogram prognostic model was performed. The calibration curve was applied to evaluate the consistency between the nomogram and the ideal observation.Results: A total of 113 patients, including 99 non-ARDS patients and 14 ARDS patients were included in this study. Eight variables including hypertension, chronic obstructive pulmonary disease, cough, lactate dehydrogenase, creatine kinase, white blood count, body temperature, and heart rate were included in the model. The area under receiver operating characteristic curve, specificity, sensitivity, and accuracy of the full model were 0.969, 1.000, 0.857, and 0.875, respectively. The calibration curve also showed good agreement between the predicted and observed values in the model.Conclusions: The nomogram can be used to predict the in-hospital incidence of ARDS in COVID-19 patients.

The Respiratory Rehabilitation Effect and Mechanism of Action of Oscillating Positive Expiratory Pressure Devices

Chronic respiratory diseases are one of the major global health problems,and their treatment and management impose a huge burden on both patients’quality of life and healthcare resources.Respiratory rehabilitation,as a non-pharmacological treatment,has received increasing attention in recent years.Oscillating positive expiratory pressure(OPEP)devices,as a new type of respiratory rehabilitation device,show good application prospects in improving respiratory function,promoting sputum expectoration,and improving quality of life.The purpose of this paper is to review the effect and mechanism of OPEP in respiratory rehabilitation.