1888年,威斯康辛州的一位电报学教师 George Parker,厌倦了整天替他的学生修理他们的笔,决心制造一支更好的笔。在这个极为单纯的动力驱使下,他开始全身心地投入到钢笔的研究和试制工作中。凭借锲而不舍的精神和过人的毅力,终于在1889...1888年,威斯康辛州的一位电报学教师 George Parker,厌倦了整天替他的学生修理他们的笔,决心制造一支更好的笔。在这个极为单纯的动力驱使下,他开始全身心地投入到钢笔的研究和试制工作中。凭借锲而不舍的精神和过人的毅力,终于在1889年12月10日研制成一支性能超越同时代产品的墨水笔“Lucky Curve”,并申请了属于派克的第一个专利。从此掀开了派克一百多年的辉煌制笔历史。展开更多
Alarm calls of the European Spermophilus citellus （EGS）, Taurus S. taurensis （TGS） and Anatolian S. xanthoprymnus （AGS） ground squirrels share the same basic structure. They are tonal sounds consisting primarily...Alarm calls of the European Spermophilus citellus （EGS）, Taurus S. taurensis （TGS） and Anatolian S. xanthoprymnus （AGS） ground squirrels share the same basic structure. They are tonal sounds consisting primarily of two different elements. The first element, often produced without the second element, has limited frequency modulation, while the second element is more frequency modulated. The present study examined whether this frequency-modulated element enhances the individual distinc- tiveness of calls, allowing calls to be ascribed with greater confidence to individual callers of the three species. Cross-validated discriminant function analysis （DFA） based on five acoustic parameters of the first element successfully classified calls to correct individuals （EGS： 90%, TGS： 98%, AGS： 96%）. Cross-validated DFA based on five acoustic parameters of the second element was also successful in classifications （EGS： 88%, TGS： 86%, AGS： 96%）, though discrimination of callers based on parameters of the second versus first element was the same for the AGS, lower for the EGS and significantly lower for the TGS. Cross-validated DFA based on five acoustic parameters of two-element calls also successfully classified calls to correct individu- als （EGS： 93%, TGS： 98%, AGS： 97%）, though did not improve the extent to which calls could be classified to individuals be- yond that based on the ftrst element alone. Thus, the second element does not enhance the individual distinctiveness of calls, but may convey other information such as the location of the caller [Current Zoology 58 （5）： 749-757, 2012].展开更多
文摘1888年,威斯康辛州的一位电报学教师 George Parker,厌倦了整天替他的学生修理他们的笔,决心制造一支更好的笔。在这个极为单纯的动力驱使下,他开始全身心地投入到钢笔的研究和试制工作中。凭借锲而不舍的精神和过人的毅力,终于在1889年12月10日研制成一支性能超越同时代产品的墨水笔“Lucky Curve”,并申请了属于派克的第一个专利。从此掀开了派克一百多年的辉煌制笔历史。
文摘Alarm calls of the European Spermophilus citellus （EGS）, Taurus S. taurensis （TGS） and Anatolian S. xanthoprymnus （AGS） ground squirrels share the same basic structure. They are tonal sounds consisting primarily of two different elements. The first element, often produced without the second element, has limited frequency modulation, while the second element is more frequency modulated. The present study examined whether this frequency-modulated element enhances the individual distinc- tiveness of calls, allowing calls to be ascribed with greater confidence to individual callers of the three species. Cross-validated discriminant function analysis （DFA） based on five acoustic parameters of the first element successfully classified calls to correct individuals （EGS： 90%, TGS： 98%, AGS： 96%）. Cross-validated DFA based on five acoustic parameters of the second element was also successful in classifications （EGS： 88%, TGS： 86%, AGS： 96%）, though discrimination of callers based on parameters of the second versus first element was the same for the AGS, lower for the EGS and significantly lower for the TGS. Cross-validated DFA based on five acoustic parameters of two-element calls also successfully classified calls to correct individu- als （EGS： 93%, TGS： 98%, AGS： 97%）, though did not improve the extent to which calls could be classified to individuals be- yond that based on the ftrst element alone. Thus, the second element does not enhance the individual distinctiveness of calls, but may convey other information such as the location of the caller [Current Zoology 58 （5）： 749-757, 2012].
