Auditory responses in avian vocal motor neurons: a motor theory for song perception in birds

The hypoglossal motor neurons that innervate the vocal organ (syrinx) of the male zebra finch show a selective, long-latency (50-millisecond) response to sound. This response is eliminated by lesions to forebrain song-control nuclei. Different song syllables elicit a response from different syringeal motor neurons. Conspecific vocalizations may therefore be perceived as members of a set of vocal gestures and thus distinct from other environmental sounds. This hypothesis is an avian parallel to the motor theory of speech perception in humans.     

A theory of self-nonself discrimination

1) Induction of humoral antibody formation involves the obligatory recognition of two determinants on an antigen, one by the receptor antibody of the antigen-sensitive cell and the other by carrier antibody (associative interaction). 2) Paralysis of antibody formation involves the obligatory recognition of only one determinant by the receptor antibody of the antigen-sensitive cell; that is, a nonimmunogenic molecule (a hapten) can paralyze antigen-sensitive cells. 3) There is competition between paralysis and induction at the level of the antigen-sensitive cell. 4) The mechanisms of low- and high-zone paralysis, and maintenance of the unresponsive state, are identical. 5) High-zone paralysis occurs when both the carrier antibody and the receptor antibody are saturated, so that associated interactions cannot take place. 6) The mechanisms of paralysis and induction for the carrier-antigen-sensitive cell are identical to those for the humoral-antigen-sensitive cell. 7) The formation of carrier-antigen-sensitive cells is thymus-dependent, whereas humoral-antigen-sensitive cells are derived from bone marrow. Since carrier antibody is required for induction, all antigens are thymus-dependent. 8) The interaction of antigen with the receptor antibody on an antigen-sensitive cell results in a conformational change in an invariant region of the receptor and consequently paralyzes the cell. As the receptor is probably identical to the induced antibody, all antibody molecules are expected to be able to undergo a conformational change on binding a hapten. The obligatory associated recognition by way of carrier antibody (inductive signal) involves a conformational change in the carrier antibody, leading to a second signal to the antigen-sensitive cell. 9) The foregoing requirements provide an explanation for self-nonself discrimination. Tolerance to self-antigens involves a specific deletion in the activity of both the humoral- and the carrier-antigen-sensitive cells.     

Speech perception takes precedence over nonspeech perception

Some components of a speech signal, when made more intense, are heard simultaneously as speech and nonspeech--a form of duplex perception. At lower intensities, the speech alone is heard. Such intensity-dependent duplexity implies the existence of a phonetic mode of perception that takes precedence over auditory modes.     

A new theory of lunar magnetism

In the hypothesis advanced here it is supposed that the field, in which rocks at the lunar surface acquired the remanent magnetization found through the Apollo project, arose from permanent magnetization of the deep interior of the moon. This theory involves the assumption that the moon, apart from a surface shell, accreted cold and remained below the Curie point of iron until sometime later than 3 x 10(9) years ago. The magnetization was acquired as the moon formed in a gas sphere in the strong magnetic field of the early sun.     

基于扎根理论的晋陕豫旅游区域品牌游客感知共词研究

以晋陕豫12个旅游景点为研究样本,通过扎根理论对游客在线评论进行关键词的提取与分析,结合词频统计及点赞数分析计算关键词的综合权重,运用Matlab和Netdraw软件构建共词矩阵并绘制共词网络,进一步通过UCINET软件对网络的结点特征和网络结构进行中心度分析,最后运用SPSS软件对共词矩阵进行聚类分析。研究表明,游客关注焦点是影响景区形象和游客满意度的关键因素,主要聚焦在生态环境、特色景观、景区管理、人文气息和旅游服务设施5个关键构面上,同时晋陕豫3省游客感知在5个构面上存在着一定差异。