还是去不起

在美国实验飞机协会今年的Air Venture航空展上,由航空界著名设计师伯特·鲁坦设计的“白色骑士2号”载机在机场跑道上空盘旋。根据其拥有者维珍银河公司的计划,“白色骑士2号”将会在美国新墨西哥州的基地起飞,将“太空船2号”运送到15240米的高度。     

给地球测体形

外形奇特的GOCE卫星将绘制精度空前的地球重力场图,它的探测数据将帮助科学家找到地震和火山爆发时间、海平面高度变化、洋流循环详情等问题的答案。     

“北极猫“护“鸟巢”

全地形消防摩托预防奥运主场馆群及周边地区火灾的发生。 “一旦发生险情,在1分钟之内这种消防车辆就能到达‘鸟巢’内的任何位置。”工作人员介绍说。这种名为“北极猫”的全地形消防摩托车身长2．4米,宽约12米,排量为650毫升,最大速度为70千米／小时。全车采用无级变速四轮驱动,不仅能够轻松地在狭窄的沙土地上行进,     

死亡区域

海水富营养化造成的浮游植物爆发对环境造成了严重破坏。[编者按]     

植被地球

植被是人类生存最基本的条件之一。为了了解世界范围内的植被水平,科学家用卫星监控了不同地区的“绿色”程度以及随季节的变化。这种观测能帮助科学家理解干旱、病虫害爆发这些自然因素以及开荒、全球变暖这些人类活动因素对植被的影响。     

人类在将海洋变成死海

人类活动对海洋的影响究竟有多大？海洋环境究竟恶化到了何种程度？为了弄清这些问题,最近科学家对复活节岛附近海域的海洋情况进行了调查,结果发现,海洋生态环境已经恶化到了异常危险的程度,包括大型海洋动物的复杂海洋食物链现在已经变成了为微生物、有毒海藻、水母和疾病主宰的简单生态系统。     

世界第一人造坑

这个被称为“米尔钻石烟斗”的人造坑位于东西伯利亚地区,在最初,它不过是偏僻峡谷中的一个“狐狸洞”,但在地质学家发现这里有巨大的钻石矿之后,经过50年的开采,它已经成为世界上最大的人造坑。它深约525米,开口处直径1610米,它是如此之大,以致人们传说在它的上空会形成气旋。连直升机和小型飞机都能被吸进去。     

Selective spatial working memory impairment in a group of children with mathematics learning disabilities and poor problem-solving skills

This study examines visual and spatial working memory skills in 35 third to fifth graders with both mathematics learning disabilities (MLD) and poor problem-solving skills and 35 of their peers with typical development (TD) on tasks involving both low and high attentional control. Results revealed that children with MLD, relative to TD children, failed spatial working memory tasks that had either low or high attentional demands but did not fail the visual tasks. In addition, children with MLD made more intrusion errors in the spatial working memory tasks requiring high attentional control than did their TD peers. Finally, as a post hoc analysis the sample of MLD was divided in two: children with severe MLD and children with low mathematical achievement. Results showed that only children with severe MLD failed in spatial working memory (WM) tasks if compared with children with low mathematical achievement and TD. The findings are discussed on the basis of their theoretical and clinical implications, in particular considering that children with MLD can benefit from spatial WM processes to solve arithmetic word problems, which involves the ability to both maintain and manipulate relevant information.