深度复制

正当代摄影家托马斯·鲁夫(Thomas Ruff)属于那种让艺术评论者头疼、无法用简单尺度进行归类的艺术家。他对摄影和图像媒介的参与性和渗透性几乎是"万花筒式"的。其作品涉及建筑、新闻、人像、天文学、色情等诸多领域,同时他也对传统或新兴图像媒体和技术具有强烈的探索欲望,并有可能是摄影界最早使用数字图像技术和网络的艺术家。     

Population growth rates in perfect contraceptive populations

Abstract Eventually, world population must cease to grow. In many countries attempts are made to decrease population growth by providing family planning services to all who want to prevent pregnancies. In this paper we use the concept 'perfect contraceptive population',(1) - a population in which no unwanted births occur - to derive estimates of the maximum contribution that prevention of unwanted births might make toward attaining a zero rate of natural increase in population.