GMS在地下水污染迁移模拟中的应用

GMS(Groundwater Modeling System)作为目前国际上流行的三维地下水数值模拟的集成软件系统,具有模块多、功能全、使用范围广、建模过程直观、操作简便等特点。该研究详细介绍了GMS在地下水污染迁移模拟中的应用流程:首先,使用MODFLOW模块建立地下水流场模型;其次,使用MT3DMS模块建立溶质(污染物)运移模型;最后,使用MODPATH模块建立地下水流迹线示踪模型。使用GMS对污染物在地下水中的迁移进行模拟预测,对地下水环境的保护具有重要积极意义,也可为制定污染物防控方案提供科学支持和理论依据。     

Influence of allelic prolamin variation and localities on durum wheat quality

Thirty-seven varieties of a Mediterranean durum wheat collection grown in Tunisia and Spain were analysed for their allelic composition in prolamins, as well as their protein concentration, sodium dodecyl sulphate sedimentation (SDSS) test and mixograph parameters. Genotype was a greater source of variation in all measurements than locality. Uncommon high and low molecular glutenin subunits (HMW-GS and LMW-GS) were found (V and 2•• subunits at Glu-A1, 13 + 16 at Glu-B1, 5* subunit and ax allele at Glu-A3). The rare combinations 2 + 4+14 + 18 and 8 + 9+13 + 16+18 subunits at the Glu-B3 locus were found. Glu-A3ax had a positive influence on SDSS and mixograph parameters. Of all the prolamins, those that have the B-LMW-GS composition aaa (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d gave the best semolina quality. By contrast, semolina quality is poor when this same composition is associated with the Glu-A1c and Glu-B1e and even poorer when associated with the Glu-A1c and Glu-B1f. In addition, the cultivars with B-LMW-GS allelic composition aab (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d, gave high quality, whereas when associated with the Glu-A1c and Glu-B1e or with Glu-A1o and Glu-B1f, the quality was very poor.     

Turf-banked terrace treads and risers, turf exfoliation and possible relationships with advancing treeline

Fine-scale geomorphic/pedogenic processes at alpine treeline may facilitate the initial stages of conifer invasion of alpine tundra. Turf-banked terraces and turf exfoliation associated with solifluction may provide both the topographic protection and the seedbed necessary for conifer establishment above treeline. The morphometry, stoniness and surface penetrability of turf-banked terraces were recorded. Whereas differences among sites exist due to topographic constraints, differences in soil penetrability depend on turf exfoliation. Exfoliated turf risers are significantly more penetrable than non-exfoliated solifluction risers and adjacent treads. These penetrable microsites provide favorable conditions for seed germination. The process of turf exfoliation may play a role in conifer advance into tundra during climatic change.     

基于MTK平台的智能手机的设计

一种基于MTK平台的智能手机的设计方案。MTK手机以MT6255为核心处理单元,外部扩展存储模块、射频模块和其它音频模块;首先对MT6255处理器进行了功能分析,然后对智能手机主要接口电路进行了详细设计,最后对MTK手机平台进行了软件结构分析。     

DTMF收发芯片MT8888的应用

MT8888芯片是MITEL公司采用CM0S工艺生产的一种低功耗、高集成度的DTMF信号收发及电话线路信号音检测芯片，它可以方便地与51单片机接口。为此，介绍了MT8888的主要功能结构及控制指令，给出了它的具体应用电路。     

Dormant Season Grazing: Effect of Supplementation Strategies on Heifer Resource Utilization and Vegetation Use

Grazing dormant forage under low-input heifer development strategies typically exposes cattle to low-quality forage. Protein supplementation while grazing dormant range can enhance heifer growth and reproductive performance. We examined resource utilization of heifers and the effects of dormant season grazing on residual vegetation characteristics under two supplementation management strategies. Approximately 100 weaned composite heifer calves were randomly selected and placed into one of two supplementation treatments in each of 2 yr, one receiving a free access 62% crude protein self-fed concentrate and the other receiving a daily hand-fed 20% crude protein cake. Grazing occurred from December (2015 and 2016) through March (2016 and 2017). Thirty transects were randomly located within each pasture for measuring vegetation quality and structure before and after grazing. Daily space use and behavior was evaluated for 21 individuals within each treatment using global positioning system (GPS) collars and resource utilization functions. Heifers supplemented with concentrated protein spent more time grazing per day than heifers supplemented with cake (6.92 ± 0.18, 6.24 ± 0.17 h). Relative use by heifers in the cake treatment was negatively related to horizontal distance from the supplement delivery site early to midwinter ($\stackrel{?}{\overline{\beta }}$ = ? 0.41 ± 0.16, ? 0.53 ± 0.17). Both treatments selected grazing locations relative to standing biomass of perennial grasses ($\stackrel{?}{\overline{\beta }}$ = 0.0005 ± 0.00004) and crude protein ($\stackrel{?}{\overline{\beta }}$ = 0.12 ± 0.007). However, resource selection was highly variable among individuals for both supplementation treatments. We found no treatment effects on pre-post grazing differences in residual cover of litter, grass, forbs and shrubs (P > 0.24). However, the time period when grazing occurred had an effect on residual vegetation conditions (P < 0.01). Our results indicate high levels of variability in grazing site selection by heifers, suggesting future research should incorporate individual animal measurements in an attempt to account for individual animal variability.     

土壤锌 镉单一及复合污染对蚯蚓金属硫蛋白含量的影响

蚯蚓金属硫蛋白(MT)是指示土壤污染程度的生物标志物.为揭示土壤镉(Cd)、锌(Zn)污染的生态效应,采用土壤染毒法,研究了Cd、Zn单一与复合污染对赤子爱胜蚓体内金属硫蛋白(MT)含量的影响.结果表明,无论是单一还是复合污染,Cd都明显诱导了蚯蚓MT的合成,随着Cd胁迫浓度和时间的增加,蚯蚓MT的含量均显著上升.与Cd相比,单一Zn污染对MT的影响要小得多,胁迫28 d后MT含量才有升高.Cd、Zn复合污染的效应在不同的Cd、Zn浓度组合下存在较大差异,同时也与暴露时间密切相关.当Cd处理为100 mg·kg-1时,Zn完全表现为拮抗作用;而在300 mg·kg-1Cd胁迫浓度下,Cd、Zn复合对MT的影响随Zn浓度和暴露时间变化而出现不同的效应:当Zn为100 mg·kg-1时,MT表现出协同-拮抗-无影响的趋势,而在500 mg·kg-1的Zn处理下,MT含量在28 d后显著下降.研究结果显示,蚯蚓MT是指示土壤Cd污染的有效指标,而Zn在一定程度上能缓解Cd对蚯蚓的毒害作用.     

低温胁迫对耐低温和非耐低温品系大黄鱼MT、AQP1、TCP1基因表达的影响

为筛选大黄鱼Larimichthys crocea耐寒基因,探寻低温胁迫对大黄鱼金属硫蛋白基因MT、水通道蛋白基因AQP1、HSP60蛋白基因TCP1表达的影响,以经过连续多代选育获得的F_5代耐低温品系大黄鱼(体质量为55.35 g±3.52 g)和非耐低温品系大黄鱼(体质量为56.45 g±4.41 g)幼鱼为试验材料,采用实时荧光定量PCR方法,研究了低温胁迫对耐低温品系大黄鱼组(N组)和非耐低温品系大黄鱼组(F组)肝脏和肌肉中MT、AQP1、TCP1基因表达水平的影响。结果表明:低温对大黄鱼MT、AQP1、TCP1基因均有不同程度的影响,且N、F组大黄鱼各基因表达量均有所差异;随着温度降低,N、F组大黄鱼肝脏和肌肉中的MT和TCP1基因表达量均呈上升趋势,在7℃时表达量均达到最高,且F组大黄鱼MT基因表达量显著高于N组(P<0.05),而N组大黄鱼TCP1基因表达量显著高于F组(P<0.05);各试验组大黄鱼肝脏和肌肉中AQP1基因表达量均随温度降低呈先升高后降低的趋势,在13℃时表达量均达到最高,在7℃时表达量均达到最低,且N组大黄鱼肝脏中的AQP1表达量显著低于F组(P<0.05),而各组肌肉中的AQP1表达量则无显著性差异(P>0.05)。研究表明,MT、AQP1、TCP1 3个基因均在大黄鱼低温适应过程中发挥重要作用,是潜在的研究大黄鱼耐寒机制的候选基因,耐低温品系和非耐低温品系大黄鱼上述3个基因在低温条件下的表达差异,也表明两个品系大黄鱼中抗寒能力存在区别。     

绵羊附睾褪黑素受体1的表达与定位

为研究褪黑素受体1（MT1）在不同年龄绵羊附睾中的表达模式,选用幼龄绵羊（2~3月龄）、青年绵羊（6~8月龄）和成年绵羊（2~3岁）的附睾,采用实时荧光定量PCR和免疫组化技术检测不同年龄绵羊附睾各部位MT1基因mRNA的表达量和MT1的分布情况。结果表明：幼龄绵羊附睾尾MT1基因的转录水平极显著高于附睾头和附睾体（P<0.01）;青年绵羊附睾体和附睾尾MT1基因的转录水平显著高于附睾头（P<0.05）;成年绵羊附睾尾MT1基因的转录水平显著高于附睾头和附睾体（P<0.05）,附睾各部位MT1基因的转录水平随年龄增长呈明显降低趋势;定位结果显示,MT1在各年龄组绵羊附睾的各个部位均有分布,且主要分布在附睾上皮细胞中。综合上述结果,不同年龄绵羊附睾的不同部位均有MT1表达和分布,并随年龄增长各部位的表达量降低,相同年龄绵羊附睾尾MT1的表达水平较高。     

低温胁迫对耐低温和非耐低温品系大黄鱼MT、AQP1、TCP1基因表达的影响

为筛选大黄鱼Larimichthys crocea耐寒基因,探寻低温胁迫对大黄鱼金属硫蛋白基因MT、水通道蛋白基因AQP1、HSP60蛋白基因TCP1表达的影响,以经过连续多代选育获得的F_5代耐低温品系大黄鱼(体质量为55.35 g±3.52 g)和非耐低温品系大黄鱼(体质量为56.45 g±4.41 g)幼鱼为试验材料,采用实时荧光定量PCR方法,研究了低温胁迫对耐低温品系大黄鱼组(N组)和非耐低温品系大黄鱼组(F组)肝脏和肌肉中MT、AQP1、TCP1基因表达水平的影响。结果表明:低温对大黄鱼MT、AQP1、TCP1基因均有不同程度的影响,且N、F组大黄鱼各基因表达量均有所差异;随着温度降低,N、F组大黄鱼肝脏和肌肉中的MT和TCP1基因表达量均呈上升趋势,在7℃时表达量均达到最高,且F组大黄鱼MT基因表达量显著高于N组(P<0.05),而N组大黄鱼TCP1基因表达量显著高于F组(P<0.05);各试验组大黄鱼肝脏和肌肉中AQP1基因表达量均随温度降低呈先升高后降低的趋势,在13℃时表达量均达到最高,在7℃时表达量均达到最低,且N组大黄鱼肝脏中的AQP1表达量显著低于F组(P<0.05),而各组肌肉中的AQP1表达量则无显著性差异(P>0.05)。研究表明,MT、AQP1、TCP1 3个基因均在大黄鱼低温适应过程中发挥重要作用,是潜在的研究大黄鱼耐寒机制的候选基因,耐低温品系和非耐低温品系大黄鱼上述3个基因在低温条件下的表达差异,也表明两个品系大黄鱼中抗寒能力存在区别。