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Humans are an unusually prosocial species-we vote, give blood, recycle, give tithes and punish violators of social norms. Experimental evidence indicates that people willingly incur costs to help strangers in anonymous one-shot interactions, and that altruistic behaviour is motivated, at least in part, by empathy and concern for the welfare of others (hereafter referred to as other-regarding preferences). In contrast, cooperative behaviour in non-human primates is mainly limited to kin and reciprocating partners, and is virtually never extended to unfamiliar individuals. Here we present experimental tests of the existence of other-regarding preferences in non-human primates, and show that chimpanzees (Pan troglodytes) do not take advantage of opportunities to deliver benefits to familiar individuals at no material cost to themselves, suggesting that chimpanzee behaviour is not motivated by other-regarding preferences. Chimpanzees are among the primates most likely to demonstrate prosocial behaviours. They participate in a variety of collective activities, including territorial patrols, coalitionary aggression, cooperative hunting, food sharing and joint mate guarding. Consolation of victims of aggression and anecdotal accounts of solicitous treatment of injured individuals suggest that chimpanzees may feel empathy. Chimpanzees sometimes reject exchanges in which they receive less valuable rewards than others, which may be one element of a 'sense of fairness', but there is no evidence that they are averse to interactions in which they benefit more than others.  相似文献   
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Cell transformation by the superoxide-generating oxidase Mox1.   总被引:65,自引:0,他引:65  
Reactive oxygen species (ROS) generated in some non-phagocytic cells are implicated in mitogenic signalling and cancer. Many cancer cells show increased production of ROS, and normal cells exposed to hydrogen peroxide or superoxide show increased proliferation and express growth-related genes. ROS are generated in response to growth factors, and may affect cell growth, for example in vascular smooth-muscle cells. Increased ROS in Ras-transformed fibroblasts correlates with increased mitogenic rate. Here we describe the cloning of mox1, which encodes a homologue of the catalytic subunit of the superoxide-generating NADPH oxidase of phagocytes, gp91phox. mox1 messenger RNA is expressed in colon, prostate, uterus and vascular smooth muscle, but not in peripheral blood leukocytes. In smooth-muscle cells, platelet-derived growth factor induces mox1 mRNA production, while antisense mox1 mRNA decreases superoxide generation and serum-stimulated growth. Overexpression of mox1 in NIH3T3 cells increases superoxide generation and cell growth. Cells expressing mox1 have a transformed appearance, show anchorage-independent growth and produce tumours in athymic mice. These data link ROS production by Mox1 to growth control in non-phagocytic cells.  相似文献   
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<正>对采自气候为非限制性因子地区的柳杉树轮稳定碳同位素比 δ13 C进行气候响应分析。用排除法消除大气二氧化碳中δ13C的变化对柳杉树轮δ13C变化的影响后,建立残差年序列RE,并结合西天目山气象站的气象记录,分析了树轮δ13C年序列对气候要素的响应。结果表明:西天目山地区树轮 δ13C的高频振荡与 11、12月最高气温的平均值,1、2、3月降水总和以及6、7月降水总和显著相关,在一定程度上反映了东亚季风对该区的影响大小。可见气候非限制性因子地区树轮稳定碳同位素组成年序列同样可以作为气候变化指针。  相似文献   
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