The role of dyking and fault control in the rapid onset of eruption at Chaitén volcano, Chile

Rhyolite is the most viscous of liquid magmas, so it was surprising that on 2?May 2008 at Chaitén Volcano, located in Chile's southern Andean volcanic zone, rhyolitic magma migrated from more than 5?km depth in less than 4?hours (ref.?1) and erupted explosively with only two days of detected precursory seismic activity. The last major rhyolite eruption before that at Chaitén was the largest volcanic eruption in the twentieth century, at Novarupta volcano, Alaska, in 1912. Because of the historically rare and explosive nature of rhyolite eruptions and because of the surprisingly short warning before the eruption of the Chaitén volcano, any information about the workings of the magmatic system at Chaitén, and rhyolitic systems in general, is important from both the scientific and hazard perspectives. Here we present surface deformation data related to the Chaitén eruption based on radar interferometry observations from the Japan Aerospace Exploration Agency (JAXA) DAICHI (ALOS) satellite. The data on this explosive rhyolite eruption indicate that the rapid ascent of rhyolite occurred through dyking and that melt segregation and magma storage were controlled by existing faults.     

FAS and NF-κB signalling modulate dependence of lung cancers on mutant EGFR

Human lung adenocarcinomas with activating mutations in EGFR (epidermal growth factor receptor) often respond to treatment with EGFR tyrosine kinase inhibitors (TKIs), but the magnitude of tumour regression is variable and transient. This heterogeneity in treatment response could result from genetic modifiers that regulate the degree to which tumour cells are dependent on mutant EGFR. Through a pooled RNA interference screen, we show that knockdown of FAS and several components of the NF-κB pathway specifically enhanced cell death induced by the EGFR TKI erlotinib in EGFR-mutant lung cancer cells. Activation of NF-κB through overexpression of c-FLIP or IKK (also known as CFLAR and IKBKB, respectively), or silencing of IκB (also known as NFKBIA), rescued EGFR-mutant lung cancer cells from EGFR TKI treatment. Genetic or pharmacologic inhibition of NF-κB enhanced erlotinib-induced apoptosis in erlotinib-sensitive and erlotinib-resistant EGFR-mutant lung cancer models. Increased expression of the NF-κB inhibitor IκB predicted for improved response and survival in EGFR-mutant lung cancer patients treated with EGFR TKI. These data identify NF-κB as a potential companion drug target, together with EGFR, in EGFR-mutant lung cancers and provide insight into the mechanisms by which tumour cells escape from oncogene dependence.     

换热管内置十字头错开塑料扭带的工作特性

为了比较普通扭带与错开扭带的工作特性,试验过程中将普通塑料扭带和十字头错开塑料扭带作为换热管的内插件,以水为工作介质,通过冷态试验,测出试验管段的压力降.选取转动效果好的内插件做热态试验.在热态试验中,管程的水被壳程的饱和蒸汽加热,测出进出口流体的温度以及饱和蒸汽的温度.在大量试验数据的基础上得出了其阻力特性和传热特性...     

基于IP网络构建视频会议系统技术

根据IP网络的主要特点,重点从网络带宽、压缩技术、多播技术、传输协议、QOS等五个方面论述了基于IP网络构建视频会议系统的技术要求.     

知识管理与数字化服务的实践与思考

进入数字图书馆时代,知识管理较好地解决了严重制约数字化服务水平提高的管理模式与服务主体不匹配的矛盾,有利于构建知识发现与创新的知识管理,更好地实现图书馆的资源导航和服务。     

预期短缺ES估计的稳定性分析

在风险管理中,风险量度估计的稳定性对金融机构的经济资本确定及风险分配起着重要的作用.本文从预期短缺(ESα)估计的稳定性角度分析重要性抽样技术和Monte Carlo模拟在估计信用资产组合ESα方面的差异.结果表明,由于组合损失分布尾部事件的稀有性,与传统的Monte Carlo模拟方法相比,运用重要性抽样方法估计的ESα比较稳定,且生成的风险贡献能够明显地体现出资产间不同的风险特征.     

极值理论(EVT)方法用于受险价值(VaR)计算的实证比较与分析

讨论了根据极值理论 ( EVT)计算受险价值 ( Va R)的两类不同的方法 :基于矩估计的“两次子样试算法”和极大似然估计法 ,并给出了各自理论推导过程和计算步骤 .同时 ,把这两类方法与正态分布和经验分布的结果进行了比较 .应用四种汇率历史数据进行的实证计算表明 ,在极端条件下 ,用极值理论方法估计 Va R具有很高的准确性 ,而矩估计法的结果又优于极大似然估计法 .