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  • Human activity affects the perception of risk by mule deer

    Human activity has been shown to influence how animals assess the risk of predation, but we know little about the spatial scale of such impacts. We quantified how vigilance and flight behavior in mule deer Odocoileus hemionus varied with distance from an area of concentrated human activity--a subalpine field station. An observer walked trails at various distances away from the station looking for deer. Upon encounter, the observer walked toward the focal animal and noted the distance at which it alerted and directed its attention to the approaching human (Alert Distance; AD), and the distance at which it fled (Flight Initiation Distance;. FID). AD and FID both increased nonlinearly with distance from the center of the field station, reaching pla- teaus around 250 m and 750 m, respectively. Deer also tended to flee by stotting or running, rather than by walking, when far from the station but they walked away when near the station. These results indicate that deer perceive lower risk near a focused area of human activity, and that vigilance and flight behaviors respond on somewhat different spatial scales. The concept of a spatial "human footprint" on behavior may be useful for understanding how human activities affect wildlife
    Mary V. PRICE,Evelyn H. STROMBOM,Daniel T. BLUMSTEIN - 动物学报(英文版)
    文章来源: 万方数据
  • 华北油田致密油直井钻探获重大突破

    截至2014年6月20日,位于华北油田冀中南部束鹿凹陷的首口致密油直井-束探3井,经大型体积压裂,在3mm油嘴放喷、井口压力29 MPa的情况下,获得日产67.32 m3高产油流.这标志着束鹿凹陷亿吨级非常规致密油由"资源"向"储量"转化迈进了坚实一步.束鹿凹陷是华北油田勘探30多年的老探区,湖相泥灰岩分布面积广,剩余油气资源丰富.但由于岩石成分多、砾级变化大及源储共生,勘探困难.华北油田从2009年开始,开展了多学科、多领域地质研究和地震攻关,并启动大型体积压裂
     - 石油机械
    文章来源: 万方数据
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