基于CMIP6的珠江流域未来干旱时空变化

干旱是一种严重且长期持续性的自然灾害,对人们的生产和生活具有显著影响。目前的大部分干旱研究将干旱的时间和空间特征进行单独分析,往往忽略了干旱的时空耦合关系。同时,南方湿润区的干旱灾害近年呈现上升趋势,探究气候变化背景下的干旱演变规律成为亟需解决的问题。因此,该研究首先利用CMIP6计算了珠江流域2015-2100年的标准化降水指数 （Standardized Precipitation Index,SPI）,应用游程理论提取干旱特征,并利用旋转经验正交函数（Rotational Empirical Orthogonal Functions,REOF）对珠江流域干湿区进行划分,再分别利用Sen''s斜率、Hurst指数方法和完备总体经验模态分解 （Complete Ensemble Empirical Mode Decomposition with Adaptive Noise,CEEMDAN）方法对气象干旱指数和干旱特征进行时空耦合特征分析。结果表明：1）根据SPI未来变化趋势,珠江流域未来将呈现更为湿润的状态,不同干湿分区的变化具有一致性且沿海分区的湿润状态更为明显。2）分析不同气候模式下CEEMDAN结果,辐射强迫的增加导致未来珠江流域干旱更为严重,未来珠江流域车旱历时处千0.5～1.8个月,干旱频率处于5.6%～13.9%之间。3）结合干旱特征的CEEMDAN分析结果,珠江流域干旱历时和干旱频率以1.04～1.31 a为主要周期,沿海分区的短周期特征更显著。该研究通过对干旱指数和干旱特征的时空耦合分析,探寻干旱的未来发展规律,为干旱研究提供了一个新的时空耦合分析视角,对干旱监测、预测预报和管理具有重要的现实意义。     

不同生长阶段花鲈生长性状与体质量的相关性

【目的】筛选出花鲈（Lateolabrax maculatus）各生长阶段对体质量有显著影响的主要生长性状,为开展花鲈选育工作时不同阶段应采取何种筛选标准提供理论依据。【方法】采用室外池塘养殖模式对花鲈（平均体质量12.29~599.33 g）开展为期250 d的养殖试验,每隔50 d随机采样测量其表型性状,包括体质量、全长、体长、眼径、头高、头长、上颌长、躯干长、尾鳍长、体高、尾长、尾柄高和吻长,并对不同生长阶段的表型性状进行相关分析、通径分析和多元回归分析,以及构建多元回归方程。【结果】在测定的13项花鲈表型性状中,除吻长外,其余性状均随养殖时间的延长而呈增长趋势。其中,花鲈的体质量从12.29±2.87 g增长至599.33±116.50 g,体长由86.73±7.75 mm增长至328.12±21.10mm。花鲈体质量和体长的变异系数波动变化均不明显,分别为19.44%~24.74%和6.43%~9.09%。不同生长阶段与花鲈体质量相关性达显著或极显著水平的生长性状分别是:养殖第1 d为全长;养殖第50 d为体长、头高和吻长;养殖第100 d为体长和体高;养殖第150 d为体长、眼径、上颌长和体高;养殖第200 d为体长、躯干长和体高;养殖第250 d为体长和头高。通径分析结果表明,养殖第1 d以全长对花鲈体质量的直接作用最大（通径系数为0.894）;养殖第50 d、第100 d、第150 d和第250 d均以体长对花鲈体质量的直接作用最大,通径系数分别为0.531、0.663、0.403和0.686;养殖第200 d则以体高对花鲈体质量的直接作用最大（通径系数为0.511）。【结论】在不同生长阶段与花鲈体质量显著或极显著相关的生长性状也各不相同。花鲈平均体质量为12.29 g时全长与体质量的相关性最大,平均体质量在70.25~599.33 g时体长与体质量的相关性较大;花鲈的体质量还与其体高和头高有相关性。因此,在花鲈选育过程中建议以体长为主要选育性状,同时辅以体高、全长和头高。     

Effect of long-term free-air CO2 enrichment on the diversity and activity of soil methanogens in a periodically waterlogged grassland

As atmospheric CO₂ levels continue to rise researchers now identify concomitant changes in plant biomass and diversity, which are postulated to alter the quality and quantity of the organic carbon entering the soil. In anoxic soils, CH₄ is the end product of the degradation of organic carbon and the system's terminal electron sink. Some soils (such as wetlands) are usually waterlogged and therefore constitute permanent CH₄ sources, while others (hydromorphic soils) are only occasionally saturated with water and alternate between acting as net CH₄ sources or sinks. Since methanogenesis is ultimately dependent on soil organic carbon, we hypothesized that a long term alteration of the latter will cause changes in type and magnitude of the former. To test this, we studied the effect of 10 years of atmospheric CO₂ enrichment on the methanogenic potential and community in a hydromorphic temperate grassland soil at the experimental Free Air Carbon dioxide Enrichment (FACE) site in Giessen, Germany. While all soils demonstrated methanogenic potential, we detected no significant changes in CH₄ production rates, lag times, methanogenic pathways, diversity, or population sizes in soils that were exposed to either 20 or 30% elevated ambient CO₂. Our findings suggest that the methanogenic potential of the soil and the methanogenic community might be insensitive to changes in atmospheric CO₂ concentrations, at least not on a decadal timescale. Thus, if our results can be extrapolated to other temporarily flooded or even wetland ecosystems, the often-observed increase in CH₄ emissions under elevated CO₂ may simply be due to an increase in labile-C input via living root and increasing fresh litter deposition, but not due to shifts in the microbial population characteristics. This could make it easier to model and extrapolate the global effect of elevated CO₂ on terrestrial CH₄ emissions.     

湖南烈士公园一、二期景观改造设计

对于老公园的改造是公园设计的难点也是重点.文章围绕设计中要"尊重历史,善待资源"去整合现有的空间,因地制宜地结合现有环境去设计,并通过具体改造方案来阐述。     

香蕉新品种——‘华农中把’的选育

‘华农中把’是以广东‘东莞中把’香蕉吸芽经60Coγ射线辐照后从诱变的植株中选育的新品种,经诱变和后续选育后稳定突变的性状为果实甜度增大。该品种主要综合性状如下:假茎高度210~265 cm,果穗近圆柱形,果穗质量21~25 kg。未熟果皮绿色,果实催熟后皮金黄色,果肉黄白色,味甜香,可溶性固形物为20.3%,可溶性糖18.1%,可滴定酸0.42%,品质优良。     

基于ANSYS Workbench的S型松土铲模态分析

在分析了S型松土铲结构特点与工作过程的基础上,利用三维CAD软件Pro/E,绘制S型松土铲的实体模型,通过有限元分析软件ANSYS Workbench对S型松土铲进行了模态分析,得到了S型松土铲的前6阶模态振型图,分析的结果为优化S型松土铲的结构和改善性能提供了理论参考。     

Expression of MMP3 in subchondral bones in early experimental osteoarthritis

AIM: To demonstrate that matrix metalloproteinase 3(MMP3)plays MMP3 play an important role in the pathogenesis of osteoarthritis by studying the expression of MMP3 in subchondral bones in early experimental osteoarthritis at gene and protein levels. METHODS: The SD rats were randomly divided into 2 groups: experimental group and control group, each containing 30 rats with similar body weight. The right knee joints of the rats in experimental group underwent surgery, which involved in both medial collateral ligament (MCL) transection and medial meniscectomy, while the animals in control group were only carried out a sham operation. The rats were killed at the 1st, 2nd and 4th weeks post-surgery to obtain the right knee joints. Pathological analysis was performed to validate this early osteoarthritic rat model. The expression of MMP3 in subchondral bones at mRNA and protein levels was evaluated by real-time polymerase chain reaction and immunohistochemical staining, respectively. RESULTS: The expression of MMP3 in subchondral bones was significantly increased at both the 1st and 2nd weeks post-surgery in experimental group, with the fold changes of 8.34 (P<0.05) and 4.85 (P<0.05), respectively, as compared with control group. No differentially expression of MMP3 was observed at the 4th week post-surgery between these 2 groups. A lot of MMP3 positive cells, including small mononuclear cells and bigger polynuclear giant cells, were found in subchondral bones in experimental group at the 1st and 2nd weeks post-surgery,but not in control group. At the 4th week post-surgery, no MMP3 positive cells were found in subchondral bones of both groups. CONCLUSION: MMP3 plays an important role in the pathogenesis of early experimental osteoarthritis.     

辣椒转录组SNP挖掘及多态性分析

 利用SNP分析软件从辣椒（Capsicum annuum L.）251 068条Unigenes中筛选出18 159个SNP,其中有1 781个SNP位点被匹配在1 291个注释基因上,基因功能分类和代谢途径分析表明,其中有853个基因参与初生代谢（28.7%）、细胞代谢（17.3%）、生物合成过程（15.7%）,另有125个（9.7%）基因序列参与新陈代谢途径,53条（4.1%）序列参与次生代谢产物合成途径,31条（2.4%）序列参与植物激素合成途径。 EST-SNP序列中4 172条（22.9%）满足设计CAPS引物条件,为了验证EST-SNP正确性,并选取了15对CAPS引物对5份辣椒材料进行扩增,结果发现有8对（53.3%）引物表现出多态性。表明筛选出这些EST-SNP标记可作为辣椒基因分型、图谱构建等的候选分子标记。     

Seagrass (Zostera marina) promotes nitrification potential and selects specific ammonia oxidizers in coastal sediments

Journal of Soils and Sediments - Seagrasses accelerate sedimentation, release oxygen and organic matter through their roots, and compete with ammonia oxidizers for ammonia/ammonium in surface...     

Protective effects of Shengfu injections on limbs in ischemia/reperfusion injury

AIM:To study the protective effects of Shengfu injections on the limbs in ischemia/reperfusion injury. METHODS:30 healthy rats at the same age were divided into 5 groups randomly. Group A was the simple reperfusion of ischemic limbs. Group B and C were injected with the Shengfu injections through femoral arteries at doses of 10 mL/kg and 20 mL/kg. Group D and E were injected with the Shengfu injections through femoral arteries at doses of 10 mL/kg and 20 mL/kg right after reperfusions. Blood samples were collected from femoral veins 1 h before femoral vessels were blocked, 1 h and 2 h after reperfusions in all animals. The concentrations of the CPK, GOT, SOD and MDA in the blood samples were determined. RESULTS:MDA increased, SOD, CPK, GOT decreased markedly in the therapeutic groups.CONCLUSION:The Shengfu injections surely protected the limbs from ischemia/reperfusion injury, the better effects was observed when the drug was administered before operation at the dose of 20 mL/kg.