海平面变化导致非洲企鹅灭绝

提到企鹅,你马上想到的不会是非洲。但有一种企鹅直到今天,依然生活在非洲南部海岸沿线。新发现的化石证实,以前非洲大陆上曾生活着多达4种企鹅。研究人员说,至于非洲多种企鹅为何灭绝,现在依然是个谜,但海平面变化可能是造成这一的重要因素。伦敦林奈学会《动物学杂志》刊登的这些化石发现代表了这些标志性海     

草莓根腐病的发生及防治

草莓根腐病是草莓生产中较难防治的土传病害。由于现阶段盛行基地化生产、一村一品等生产经营模式，使到一些生产者在土地有限的情况下多年在同一地块上反复种植草莓，同时又缺乏合理轮作，致使病害流行，该病严重时可造成整个草莓园毁灭，且有逐年上升趋势，已成为草莓生产进一步发展的主要障碍之一。     

国外科技期刊亮点

温度上升将致西南极冰盖融化，发现与两种不同抗原结合的抗体，基因过度表达与胰腺癌发病有关，食用红肉过量易患视网膜黄斑病变，改造噬菌体以提升抗生素药效。     

“沧海桑田”：一件揭示重大环境问题的展品

天津科技馆展厅中有一件展品——“天津海岸带变迁及贝壳堤分布”，又名“沧海桑田”。该展品形象地表现了历史上不同时期天津海岸带的演化进程，旨在警示人们从历史看未来：全球气候变暖，海平面上升及海岸线进蚀是重大的地区环境问题，应当引起我们的高度关注。     

有压管道中排气速度与管道压力的关系

集中供热、城市输配水管道常出现管道爆管,给工业生产,居民生活带来严重影响,经有关方面的专家分析,其主要原因是管道排气不畅引发水锤造成的,然而,工程实际中,管道排气装置的合理选择及正确安装都未得到足够的重视。基于此,我们模拟工程实际中排气阀工作状态下的环境,根据实验数据,分析了管道排气速度与管道压力及管道中液面上升与管道中压力之间的关系,希望能对合理正确选择排气阀有所帮助。     

全球变暖的惊人事实

全球变暖是指全球气温升高。近一百多年来，全球平均气温经历了“冷-暖-冷-暖”两次波动，总体为上升趋势。这种气候变暖的主要原因是人类在近一个世纪以来大量使用了矿物燃料，排放了大量的温室气体所致。而全球变暖的后果，则会使全球的降水量重新分配，冰川和冻土消融，海平面上升，既危害自然生态系统的平衡，更威胁人类的食物供应和居住环境。[编者按]     

胰腺癌介入诊疗新技术的研究

胰腺癌是消化系统中较常见的恶性肿瘤，具有发现晚、转移早、进展快、预后差的特点。近数十年来，其发病率在全世界范围内逐年上升，位居恶性肿瘤的第13位，预后极差；死亡率高居恶性肿瘤的第8位。国人胰腺癌发病率亦呈上升趋势。据北京、上海等地的统计数据显示：胰腺癌发病率位于恶性肿瘤的第9～10位，死亡率位于第6～7位。由于胰腺癌早期诊断的困难性、肿瘤的侵袭性和缺乏有效、成熟的系统综合治疗手段，     

来自全球气候预测网站的预报:全球气温可能上升11℃

根据世界上最大的气候建模研究的结果，温室效应可能要比专家们以前所预言的情形严重得多得多。在最坏的情形下，与前工业时代相比，翻了一番的二氧化碳浓度将使全球气温平均上升11℃以上。但是，除了预言更大范围的最大温升以外，该项目也扩大了温度可能变化的范围。     

Paleoceanographic records in the sedimentary cores from the middle Okinawa Trough

Two gravity piston cores (Cores 155 and 180) involved in this study were collected from the middle Okinawa Trough. Stratigraphy of the two cores was divided and classified based on the features of planktonic foraminifera oxygen isotope changes together with depositional sequence,millennium-scale climatic event comparison, carbonate cycles and AMS^14C dating. Some paleoclimatic information contained in sediments of these cores was extracted to discuss the paleoclimatic change rules and the short-time scale events presented in interglacial period. Analysis on the variation of oxygen isotope values in stage two shows that the middle part of the Okinawa Trough may have been affected by fresh water from the Yellow River and the Yangtze River during the Last Glacial Maximum (LGM). The oxygen isotope value oscillating ranges of the cores have verified that the marginal sea has an amplifying effect on climate changes.The δ^13C of benthic foraminifera Uvigerina was lighter in the glacial period than that in the interglacial period, which indicates that the Paleo-Kuroshio‘s main stream moved eastward and its influence area decreased. According to the temperature difference during the “YD” period existing in Core 180 and other data, we can reach the conclusion that the climatic changes in the middle Okinawa Trough area were controlled by global climatic changes, but some regional factors had also considerable influence on the climatechanges. Some results in this paper support Fairbanks‘s point that the “YD” event was a brief stagnation of sea level rising during the global warming up procession. Moreover,the falling of sea level in the glacial period weakened the exchange between the bottom water of the Okinawa Trough and the deep water of the northwestern Pacific Ocean and resulted in low oxygen state of bottom water in this area.These procedures are the reasons for carbonate cycle in the Okinawa Trough area being consistent with the “Atlantic type”carbonate cycle.