我们死亡时发生了些什么？

斯蒂斐（以下简称“斯”）：这项研究采用什么方法来考察并核实人们宜称的有关“濒死体验”的描述？ 山姆·帕尼亚（以下简称“帕”）：当你的心脏停止跳动时。就不会有血液进入你的大脑。而接下来将会发生的，就如同你可以想象到的那样——在1O秒内，大脑的活动完全停止。然而。反常的是，在经历过心跳停止（其中既包括心跳停止几分钟的。也包括心跳停止1小时以上的）后又被从鬼门关上抢救过来的人群中。有10％至20％的人报告说他们当时是有意识的。     

A microbial oasis in the hypersaline Atacama subsurface discovered by a life detector chip: implications for the search for life on Mars

The Atacama Desert has long been considered a good Mars analogue for testing instrumentation for planetary exploration, but very few data (if any) have been reported about the geomicrobiology of its salt-rich subsurface. We performed a Mars analogue drilling campaign next to the Salar Grande (Atacama, Chile) in July 2009, and several cores and powder samples from up to 5?m deep were analyzed in situ with LDChip300 (a Life Detector Chip containing 300 antibodies). Here, we show the discovery of a hypersaline subsurface microbial habitat associated with halite-, nitrate-, and perchlorate-containing salts at 2?m deep. LDChip300 detected bacteria, archaea, and other biological material (DNA, exopolysaccharides, some peptides) from the analysis of less than 0.5?g of ground core sample. The results were supported by oligonucleotide microarray hybridization in the field and finally confirmed by molecular phylogenetic analysis and direct visualization of microbial cells bound to halite crystals in the laboratory. Geochemical analyses revealed a habitat with abundant hygroscopic salts like halite (up to 260?g kg(-1)) and perchlorate (41.13?μg g(-1) maximum), which allow deliquescence events at low relative humidity. Thin liquid water films would permit microbes to proliferate by using detected organic acids like acetate (19.14?μg g(-1)) or formate (76.06?μg g(-1)) as electron donors, and sulfate (15875?μg g(-1)), nitrate (13490?μg g(-1)), or perchlorate as acceptors. Our results correlate with the discovery of similar hygroscopic salts and possible deliquescence processes on Mars, and open new search strategies for subsurface martian biota. The performance demonstrated by our LDChip300 validates this technology for planetary exploration, particularly for the search for life on Mars.     

Putative fossilized fungi from the lithified volcaniclastic apron of Gran Canaria, Spain

We report the discovery of fossilized filamentous structures in samples of the lithified, volcaniclastic apron of Gran Canaria, which were obtained during Leg 157 of the Ocean Drilling Program (ODP). These filamentous structures are 2-15 μm in diameter and several hundred micrometers in length and are composed of Si, Al, Fe, Ca, Mg, Na, Ti, and C. Chitin was detected in the filamentous structures by staining with wheat germ agglutinin dye conjugated with fluorescein isothiocyanate (WGA-FITC), which suggests that they are fossilized fungal hyphae. The further elucidation of typical filamentous fungal morphological features, such as septa, hyphal bridges, and anastomosis and their respective sizes, support this interpretation. Characteristic structures that we interpreted as fossilized spores were also observed in association with the putative hyphae. The fungal hyphae were found in pyroxene phenocrysts and in siderite pseudomorphs of a basalt breccia. The fungal colonization of the basalt clasts occurred after the brecciation but prior to the final emplacement and lithification of the sediment at ～16-14 Ma. The siderite appears to have been partially dissolved by the presence of fungal hyphae, and the fungi preferentially colonized Fe-rich carbonates over Fe-poor carbonates (aragonite). Our findings indicate that fungi may be an important geobiological agent in subseafloor environments and an important component of the deep subseafloor biosphere, and that hydrothermal environments associated with volcanism can support a diverse ecosystem, including eukaryotes.     

局部裂开介质中的流动校正算子

文章证明了一个局部裂开介质中的流动均质化校正算子的结果。在参考文献[3]中Clark和Sbowalter用二维收敛技巧研究了均质化问题。     

碾压砼的抗冻性

碾压砼正在迅速地变成一种普通的建筑材料。现在越来越多的路面，机场道面和停车场都采用碾压砼。文中介绍了这种材料的施工工艺和提高抗冻性采取的措施。     

平台旋转对STAP性能的影响

研究了平台旋转尤其是天线旋转对杂波有限的前视机载雷达应用中空时自适应处理（STAP）性能的影响。提出了影响性能的两种主要机理。一种是天线旋转时角多普勒空间中杂波表面的形状变化。当这种机理占优势时，尽管应用运动补偿相位延迟控制可以减轻偏航引起的问题，但是STAP在横滚时比偏航时更能恢复原状。另一种是STAP数据矢量的不连续性急剧转变的存在，对此，一种可能原因是天线的非理想运动补偿控制。实际上这些不连续性增大了带宽并且导致性能明显下降。     

NASA地球观测系统的数据和信息系统(EOSDIS)——处理、归档并分配大量地球科学图象及有关产品的综合系统

地球观测系统数据及信息系统(EOSDIS)正在NASA哥达德航天中心进行开发,目的是建立一个包含15年数据的综合性全球数据库,数据量达几拍它(1拍它=10~(15))。EOSDIS将指挥和控制一系列EOS卫星,进行分布式数据处理,并在8个服务站进行数据归档和分配服务。本文介绍了EOSDIS的核心部件,主要是规划和处理科学数据产品的功能。     

利用遥测信号无线电干涉仪的初始段安全系统

靶场安全问题随导弹性能的提高日趋重要。在发射场附近这一问题更为突出,因为这里导弹爆炸能量最大。诸如雷达、GPS外测系统和光测因多种原因在这里用得不多,故需要一种设备能在导弹起飞后头几秒内提供有用的外测数据。该设备能提供从发射台起飞直到120秒内的导弹偏离理论弹道的数据。 本文叙述的外测系统利用了无线电干涉仪的原理,从两个精密间隔的天线提取相位差测量值。这些测量值送往“试验显示设施”,转换成常用的角偏差曲线,供靶场安全人负使用。 本文介绍了无线电干涉仪系统的基本概念,这种特殊外测系统的设置和使用情况。并详细介绍了这种设备的射前演练、设置以及实时显示的设置和最终数据产品的输出。     

用于对簇叶下地面目标成像的双基地超宽带SAR雷达

比较了双基地SAR与单基地SAR有关的特性，例如相参积累时间和空间分辨率。提出双基地SAR可用于抑制地面杂波，例如在杂波散射由二面或三面散射机理为主产生的时候。将这一概念用于使用VHF频段SAR探测隐蔽在簇叶中的机动车辆。电磁仿真显示，双基地SAR收、发机选择不同的入射角可以大大提高车辆对杂波的信杂比。