黄浦江上游近自然混交林和人工纯林水源涵养功能评价

以上海黄浦江上游水源涵养林为研究对象,选择近自然混交林、香樟(Cinnamomum camphora)人工纯林和无患子(Sapindus mukorossi)人工纯林,对比了地上部分、枯落物层、土壤层三个垂直层次的持水量,综合评价了其水源涵养功能。结果表明:地上部分持水量近自然混交林与香樟纯林持平,大于无患子纯林,分别为16.36t/hm2,16.85t/hm2,12.54t/hm2;枯落物层最大持水量依次为近自然混交林(0.37t/hm2)无患子纯林(0.004t/hm2)香樟纯林(0.003t/hm2);土壤层最大持水量近自然混交林(2 657.02t/hm2)无患子纯林(2 526.81t/hm2)香樟纯林(2 474.80t/hm2)。土壤层对森林涵养水源功能的贡献最大,但同时离不开地上部分及枯落物层三者间的相互依存和影响。综合评价得到不同类型林分的总持水量为近自然混交林(2 673.73t/hm2)无患子纯林(2 539.35t/hm2)香樟纯林(2 491.65t/hm2)。由此可见,林分复杂、树种多样、林下植被丰富的近自然混交林涵养水源的能力最强,优于单一的无患子纯林,而香樟纯林最差。     

Chemical speciation of copper and manganese in solution of a copper-contaminated soil and young grapevine growth with amendment application

Copper(Cu)-based fungicide application to control foliar diseases in grapevine(Vitis vinifera L.) can increase soil Cu availability. Brazilian soils have high natural Cu and manganese(Mn) concentrations, increasing the potential for toxicity to grapevine plants. Application of amendment substances can reduce the concentrations of toxic chemical species of Cu and Mn in soil solution, especially for the soils grown with young plants. We evaluated the chemical speciation of Cu and Mn in soil soluti...     

高寒区多源降水产品精度与水文模拟效果评估——以雅鲁藏布江流域和拉萨河流域为例

卫星降水产品在缺资料地区开展水文气象研究及径流模拟中发挥着至关重要的作用,然而卫星降水产品的精度可能会影响径流模拟效果。采用多种统计指标和VIC水文模型综合评估5种卫星降水产品(CMORPH-BLD、GSMaP＿Gauge、CMFD、MSWEP和PERSIANN-CDR)在雅鲁藏布江流域的精度和拉萨河流域的水文模拟效果。结果表明：(1)CMORPH＿BLD和GSMaP＿Gauge在少雨季存在低估,CMFD在少雨季与观测值具有很好的一致性。MSWEP和PERSIANN-CDR在多雨季和少雨季存在高估。降水量方面,CMORPH-BLD和CMFD均较为接近观测值,其他降水产品存在不同程度的高估。(2)日尺度上,除CMFD外其他卫星降水数据与观测值具有较小的相关性(0.26～0.45),CMORPH-BLD和CMFD和观测值具有较好的一致性,CMFD和MSWEP探测小降水事件(0.1,0.5,1 mm/d)的能力优于GSMaP＿Gauge。各卫星降水产品在探测强降水(2,5,10 mm/d)方面能力不足。日降水2 mm/d的降水阈值为各分类指数的变化点。(3)月尺度上,各降水产品与观测值具有很...     

Method for estimation of ocean current velocity from satellite images

Barotropic instability waves on a shear interface propagate at the average speed of the water on the two sides. Assuming the instability to be excited by tidal oscillations, the phase speed is the wavelength divided by the tidal period. If the water is at rest on one side of the shear layer the current speed on the other side can be calculated. This method, applied to the Gulf Stream beyond Cape Hatteras as seen in satellite images, gives estimates of current speed in general agreement with in situ observations.     

细胞质对普通小麦面包加工品质的影响

为探明不同胞质背景对杂种小麦面包JJD-r品质的影响,测定了4个强筋品种与4个中弱筋品种按NCⅡ设计配制的32个正反交组合及T型、K型、AL型、A型4种胞质背景的14个组合的F2籽粒的硬度、GMP含量,Zeleny沉淀值、面团流变学参数和面包体积等面包加工品质性状.结果表明:①强筋组亲本对除吸水率和评价值之外的其他面包加工品质性状均具有显著的有利于面包加工品质的普遍胞质效应;豫麦34、郑麦9023和陕优225在多个面包加工品质性状方面具有显著有利的一般胞质效应;陕优225的面包体积的一般胞质效应为14 mL,达到5%的显著水平.因此,在面包小麦育种中要注意安排强筋亲本作母本.②就面包体积而言,T型和K型不育胞质相对于A型胞质具有有利的一般胞质效应,AL型不育胞质与A型胞质相当.组合T-西农772 X AL-RI的T型不育胞质的个别胞质效应为60 mL,组合K-西农772 X T6-3的K型不育胞质的个别胞质效应为98 mL,且均达5%的显著水平.T,K和AL型不育胞质可用于面包小麦杂种优势利用.     

Toxicity and antioxidant activity in vitro and in vivo of two Fucus vesiculosus extracts

The consumption of seaweeds has increased in recent years. However, their adverse and beneficial effects have scarcely been studied. Two extracts from the brown seaweed Fucus vesiculosus containing 28.8% polyphenols or 18% polyphenols plus 0.0012% fucoxanthin have been obtained and studied to determine their toxicity in mice and rats and also their antioxidant activity. Both extracts were shown to lack any relevant toxic effects in an acute toxicity test following a 4 week daily treatment in rats. The extracts exhibited antioxidant activity in noncellular systems and in activated RAW 264.7 macrophages, as well as in ex vivo assays in plasma and erythrocytes, after the 4 week treatment in rats. Our ex vivo results indicated that compounds from extract 2 may be more easily absorbed and that the antioxidants in their parent or metabolized form are more active. These findings support the view that the daily consumption of F. vesiculosus extract 2 (Healsea) would have potential benefits to humans.     

Eighth millennium pottery from a prehistoric shell midden in the brazilian Amazon

The earliest pottery yet found in the Western Hemisphere has been excavated from a prehistoric shell midden near Santarém in the lower Amazon, Brazil. Calibrated accelerator radiocarbon dates on charcoal, shell, and pottery and a thermoluminescence date on pottery from the site fall from about 8000 to 7000 years before the present. The early fishing village is part of a long prehistoric trajectory that contradicts theories that resource poverty limited cultural evolution in the tropics.     

醋酸铅对体外培养大鼠大脑皮质神经细胞形态的影响

为了观察醋酸铅对神经细胞的形态学影响,通过建立体外培养大鼠大脑皮质神经细胞模型,应用不同浓度醋酸铅(0,50,100,200,400μmol/L)与神经细胞分别培养3、6、12、24 h,倒置相差显微镜观察细胞形态变化.结果显示,醋酸铅与神经细胞共同培养12~24 h,细胞密度降低,胞体变小,突起缩短;随醋酸铅浓度递增,细胞形态较对照组差异愈加显著(P<0.05).表明染铅浓度与神经细胞形态变化存在剂量效应与时间效应关系.