Frequency of decompression illness among recent and extinct mammals and “reptiles”: a review

The frequency of decompression illness was high among the extinct marine “reptiles” and very low among the marine mammals. Signs of decompression illness are still found among turtles but whales and seals are unaffected. In humans, the risk of decompression illness is five times increased in individuals with Patent Foramen Ovale; this condition allows blood shunting from the venous circuit to the systemic circuit. This right-left shunt is characteristic of the “reptile” heart, and it is suggested that this could contribute to the high frequency of decompression illness in the extinct reptiles.     

“Bicellar” Lipid Mixtures as used in Biochemical and Biophysical Studies

Over the past decade “bicellar” lipid mixtures composed of the long-chain dimyristoyl phosphatidylcholine (DMPC) and the short-chain dihexanoyl PC (DHPC) molecules have emerged as a powerful medium for studying membrane associated, biologically relevant macromolecules and assemblies. Depending on temperature, lipid concentration and composition these lipid mixtures can assume a variety of morphologies, some of them alignable in the presence of a magnetic field. This article will examine the biophysical studies that have elucidated the various morphologies assumed by these lipid mixtures, and their use in the biochemical studies of biomolecules.

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Tracking pigeons in a magnetic anomaly and in magnetically “quiet” terrain

Pigeons were released at two sites of equal distance from the loft, one within a magnetic anomaly, the other in magnetically quiet terrain, and their tracks were recorded with the help of GPS receivers. A comparison of the beginning of the tracks revealed striking differences: within the anomaly, the initial phase lasted longer, and the distance flown was longer, with the pigeons' headings considerably farther from the home direction. During the following departure phase, the birds were well homeward oriented at the magnetically quiet site, whereas they continued to be disoriented within the anomaly. Comparing the tracks in the anomaly with the underlying magnetic contours shows considerable differences between individuals, without a common pattern emerging. The differences in magnetic intensity along the pigeons' path do not differ from a random distribution of intensity differences around the release site, indicating that the magnetic contours do not directly affect the pigeons' routes. Within the anomaly, pigeons take longer until their flights are oriented, but 5 km from the release point, the birds, still within the anomaly, are also significantly oriented in the home direction. These findings support the assumption that magnetically anomalous conditions initially interfere with the pigeons' navigational processes, with birds showing rather individual responses in their attempts to overcome these problems.     

Male fighting and “territoriality” within colonies of the ant Cardiocondyla venustula

The ant genus Cardiocondyla is characterized by a bizarre male polymorphism with wingless fighter males and winged disperser males. Winged males have been lost convergently in several clades, and in at least one of them, wingless males have evolved mutual tolerance. To better understand the evolutionary pathways of reproductive tactics, we investigated Cardiocondyla venustula, a species, which in a phylogenetic analysis clusters with species with fighting and species with mutually tolerant, wingless males. Wingless males of C. venustula use their strong mandibles to kill freshly eclosed rival males and also engage in short fights with other adult males, but in addition show a novel behavior hitherto not reported from social insect males: they spread out in the natal nest and defend “territories” against other males. Ant males therefore show a much larger variety of reproductive tactics than previously assumed.     

“虎虎”生“威”“洲”老虎

<正>2007年,一场"周老虎"事件闹得沸沸扬扬。陕西村民周正龙宣称在野外拍摄到濒危动物野生华南虎的照片,后来又被证实为弄虚作假,嘘声一片。此次,我们再去探访华南虎,见到的育虎专家"洲老虎"则是名副其实、成果斐然。他用富有传奇色彩的个人经历和实实在在的工作业绩表明,真英雄可以不问出处,有志者必能成就大事。     

“限塑令”的“堵”与“疏”

保证“限塑令”有效实施的关键,在于如何实现塑料袋“少用一点,回收一点,替代一点,降解一点”;尽量做到“能不用就不用,一定要用就少用,多次重复用,不能用时回收再利用”。     

“坟场”与“打鬼”

一阵旋风刮得漫天皆白。一只只断了线的风筝，失 去控制地向人们头上栽来，人们抱着脑袋飞跑，尽快逃离这白色旋风。这是城市常见的一幕 这不是天外来的飞碟，也不是夜间的噩梦，这是最实实在在的生活。不过倒不必担心飞砂走石的袭击，这是轻得几乎没有分量的塑料袋，但它的污秽却使人如同躲进一场细菌战。 “忽然一夜春风来，千树万树梨花开”，岑参当年有诗但道那塞外风雪威猛，征人虽然艰苦，却很有诗意。而令城市绚烂多彩，生活优裕，却是“忽然一阵朔风来，漫天遍地皆飞白”，它没有诗意，只撒播一片“白色恐怖”。像送葬的纸钱，压抑…     

“绿色通道”与“防火墙”

"项目要上马、经济要发展,同时要依法履行环评管理规定和程序,要做到两者兼顾非常不容易"。——广东省环境保护厅厅长李清作为环保工作中与经济建设结合最为紧密的一环,环评是环保工作的第一审批权,也始终是环保工作的重中之重。随着近年经济社会的发展,环评审批更成为调整经济结构、促进经济转型的重要抓手。为此,环保部长周生贤要求,对环评既要开辟"绿色通道",也要设置"防火墙"。环保部副部长潘岳也曾说,解决环境问题的关     

“噪声”“噪音”辨析

近来,人们常常自觉或不自觉地混淆“噪声”和“噪音”两个不同词的概念,甚至以为它们在意义上是相同的。其实是有区别的。“噪”字古写作“喿”,以象群鸟集于树上争鸣之形。《辞海》释“噪”为“群鸣”便是从其古义出发的。对“噪声”一词《辞海》是这样解释的:“不同频率和不同强度的声音,无规律     

“带走”与“留下”

笔者外出到一个著名的旅游景点游览,见到一张印刷精致的小小游览卷上,印有耐人寻味的二句话:除了摄影,请您什么也别带走;除了足迹,请您什么也别留下。这一提醒,别出心裁,令人感慨万千。 旅游景点,是属于大家的,游人来此观光,欣赏大自然巧夺天工的美景,别有洞天的     

“着急”差点“要命”

2010年的某一天,我正在PVC包装生产线上工作着,突然码垛机停了,我快步跑向现场处理停机事故,着急中,忘记了脚下离地面约10cm的供气管线,一步就给拌倒了,只听“咣”的一声,正好摔在了供盘传送机框边上一个约5cm长的螺丝杆上,     

“杂牌军”博弈“正规军”

当家里的废旧物品多了，大家第一时间想到的。往往都是卖给那些走街串巷收废品的。这些人多是骑着一辆板车，放着一杆盘秤，穿梭在居民楼之间，要么举着一个大喇叭，要么就直接扯着嗓门吆喝：“收破烂儿啦!”、“破烂换钱!”……而如果您刚刚找了一个这样的废品收购者，然后正提着东西要去出售，这时对面突然有一辆整洁的汽车开过来，从上面下来几个穿着统一制服的工作人员，拿着标准的量具，彬彬有礼地对您说，“您是有废品需要回收吗？”两相比较，您如何选择呢？     

“引进”与“过失”

时下某些腰包鼓起来的‘款爷’,对‘洋’字情有独钟,喝‘洋’酒,抽‘洋’烟,穿‘进口’的名牌,用的也是非‘进口’不要,与‘洋’攀亲,身价倍增,足可见唯‘洋’情结对国人能产生如此大的‘挡不住的诱惑’力。 但说起来也不必大惊小怪,你有钱,花钱是你的自由,替商家创利,还来个‘洋为中用’谁管的着你高消     

“丢下”与“捡起”

南来北往的旅人,正急匆匆行进在某大都市的火车站广场,只见一衣着时髦的女子与一西装革履的小年青,一边提着旅行装,一边剥着香蕉,将香蕉皮随手丢到车站广场上,不一会儿,臂扎红袖章的老者,提着畚斗,弯着腰,捡起地上的香蕉皮。 这是在许多人看来都是“司空见惯”的镜头,大可不必小题大作,其实不然。     

“金凤凰”飞进“夹皮沟”

被称为“夹皮沟”的红岩煤矿随着矿容矿貌的改观,青年矿工也越来越受到姑娘们的青睐。去年有143名外地“金凤凰”与青年矿工喜结良缘。 红岩煤矿是重庆南桐矿务局最偏远的矿井,昔日矿山黑、脏、臭、乱,矿工找对象成了     

“保值”与“贬值”

如今 ,招工单位、用人单位对人才的要求越来越“苛刻”,可谓“门槛”越来越高 ,无一技之长 ,肚里没多少“油水”者 ,终将挡在门外 ,只能望“门”兴叹 ,并由感而发出“早知如此 ,何必当初”。这不能怪用人单位不选择你 ,怪只能怪自己。的确 ,当今社会对人才的要求越来越高。一个人如果单靠原有的一张文凭、一种技能 ,想在职场立足几乎是不可能的。现在 ,不少下岗职工急于求职 ,却忽视参加培训学习 ,更新知识。有的认为自己有一技之长 ,无需“充电”,这必将被残酷的市场竞争所淘汰。二十一世纪已步入知识经济时代 ,社会对人才的需求也发生了质…     

关注“错误”留住“意外”共享“精彩”

美国著名的教育家布鲁纳曾说过:"学生的错误都是有价值的。"正确,可能只是一种模仿;错误,却绝对是一种经历。学习本身就是一个不断尝试错误的过程,学生正是在不断地发生错误、纠正错误的过程中获得了丰富的知识,提高了学习的能力、增进了情感的体验。只要我们积极对待,及时抓取,细心呵护,用心挖掘,引导巧妙,从"错误"中也能生成精彩,为数学教学添上一道亮丽的风景线。     

“可以快速” “而正确地” “看到气味”

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