A ratchet mechanism for amplification in low-frequency mammalian hearing

The sensitivity and frequency selectivity of hearing result from tuned amplification by an active process in the mechanoreceptive hair cells. In most vertebrates the active process stems from the active motility of hair bundles. The mammalian cochlea exhibits an additional form of mechanical activity termed electromotility: its outer hair cells (OHCs) change length upon electrical stimulation. The relative contributions of these two mechanisms to the active process in the mammalian inner ear is the subject of intense current debate. Here we show that active hair-bundle motility and electromotility can together implement an efficient mechanism for amplification that functions like a ratchet: sound-evoked forces acting on the basilar membrane are transmitted to the hair bundles whereas electromotility decouples active hair-bundle forces from the basilar membrane. This unidirectional coupling can extend the hearing range well below the resonant frequency of the basilar membrane. It thereby provides a concept for low-frequency hearing that accounts for a variety of unexplained experimental observations from the cochlear apex, including the shape and phase behavior of apical tuning curves, their lack of significant nonlinearities, and the shape changes of threshold tuning curves of auditory nerve fibers along the cochlea. The ratchet mechanism constitutes a general design principle for implementing mechanical amplification in engineering applications.Comment: 6 pages, 4 figures, plus Supplementary Information. Animation available on the PNAS website (http://dx.doi.org/10.1073/pnas.0914345107)

Inner-ear abnormalities and their functional consequences in Belgian Waterslager canaries (Serinus canarius)

Recent reports of elevated auditory thresholds in canaries of the Belgian Waterslager strain have shown that this strain has an inherited auditory deficit in which absolute auditory thresholds at high frequencies (i.e. above 2.0 kHz) are as much as 40 dB less sensitive than the thresholds of mixed-breed canaries and those of other strains. The measurement of CAP audiograms showed that the hearing deficit is already present at the level of the auditory nerve (Gleich and Dooling, 1992). Here we show gross abnormalities in the anatomy of the basilar papilla of Belgian Waterslager canaries at the level of the hair cell. The extent of these abnormalities was correlated with the amount of hearing deficit as measured behaviorally

The Pharisees Pre-70

In 70 C.E. the Romans razed the Jerusalem Temple 2nd Judaism underwent a radical change. From that moment, normative Judaism was Pharisaic Judaism. As a result, our knowledge of the Pharisees after 70 C.E. is as extensive as our knowledge of the Pharisees before 70 C.E. is limited. When did the Pharisees first arise? What were their beliefs and practices? What role did they play in the growth of early Judaism? These questions have haunted scholars for decades and have given birth to a myriad of diverse theories. It is the purpose of this project to examine five of these hypotheses and then to offer some modest conclusions concerning the future of pre-70 Pharisaic scholarship.Master of Arts (MA

Assessing Trends and Decomposing Change in Nonresponse Bias: The Case of Bias in Cohort Distributions

Survey research is still confronted by a trend of increasing nonresponse rates. In this context, several methodological advances have been made to stimulate participation and avoid bias. Yet, despite the growing number of tools and methods to deal with nonresponse, little is known about whether nonresponse biases show similar trends as nonresponse rates and what mechanisms (if any) drive changes in bias. Our article focuses on biases in cohort distributions in the U.S. and German general social surveys from 1980 to 2012 as one of the key variables in the social sciences. To supplement our cross-national comparison of these trends, we decompose changes into within-cohort change (WCC) and between-cohort change. We find that biases in cohort distributions have remained relatively stable and at a relatively low level in both countries. Furthermore, WCC (i.e., survey climate) accounts for the major part of the change in nonresponse bias

The Interorganizational Relationships of a Public Welfare Agency

The American social welfare field is best characterized as a highly decentralized sphere of activity in which autonomous organizations define and pursue their goals in a fairly independent fashion. The complex nature of modern social problems, however, requires concerted action by a variety of organizations if effective solutions are to be developed. This conflict between the structural nature of the welfare field and the demands of the problems to be addressed has meant that social welfare planners have had to be concerned with the conditions affecting the willingness of independent organizations to engage in cooperative activities with each other. The purposes of the present paper are twofold: (1) To identify some of the major variables that affect the interorganizational activities of social welfare organizations; and (2) to describe the actual interorganizational patterns of one such organization, a county board of public assistance

Growth or decline in the Church of England during the decade of Evangelism: did the Churchmanship of the Bishop matter?

The Decade of Evangelism occupied the attention of the Church of England throughout the 1990s. The present study employs the statistics routinely published by the Church of England in order to assess two matters: the extent to which these statistics suggest that the 43 individual dioceses finished the decade in a stronger or weaker position than they had entered it and the extent to which, according to these statistics, the performance of dioceses led by bishops shaped in the Evangelical tradition differed from the performance of dioceses led by bishops shaped in the Catholic tradition. The data demonstrated that the majority of dioceses were performing less effectively at the end of the decade than at the beginning, in terms of a range of membership statistics, and that the rate of decline varied considerably from one diocese to another. The only exception to the trend was provided by the diocese of London, which experienced some growth. The data also demonstrated that little depended on the churchmanship of the diocesan bishop in shaping diocesan outcomes on the performance indicators employed in the study

Understanding Respondents' Attitudes Toward Web Paradata Use

The collection and use of paradata is gaining in importance, especially in web surveys. From a research ethics’ perspective, respondents should be asked for their consent to the collection and use of web paradata. In this context, a positive attitude toward paradata use has been deemed to be a prerequisite for respondents’ willingness to share their paradata. The present study aimed to identify factors affecting respondents’ attitudes toward paradata use. Our findings revealed that adequately informing survey respondents about what paradata are and why they are used was an important determinant of their attitudes toward paradata use. Moreover, we found that respondents with a positive attitude toward the survey were more likely to have a favorable opinion of paradata use. Our findings suggest that a thorough understanding of the factors that contribute to a positive attitude toward paradata use provides the basis for improved paradata consent procedures, which in turn will increase rates of consent to paradata use and help attenuate the risk of consent bias in web surveys

A Note on How Prior Survey Experience With Self-Administered Panel Surveys Affects Attrition in Different Modes

Attrition poses an important challenge for panel surveys. With respect to these surveys, respondents’ decisions about whether to participate in reinterviews are affected by their participation in prior waves of the panel. However, in self-administered mixed-mode panels, the way of experiencing a survey differs between the mail mode and the web mode. Consequently, this study investigated how respondents' prior experience with the characteristics of a survey - such as length, difficulty, interestingness, sensitivity, and the diversity of the questionnaire - affects their informed decision about whether to participate again or not. We found that the length of a questionnaire seems to be of such importance to respondents that they base their participation on this characteristic, regardless of the mode. Our findings also suggest that the difficulty and diversity of questionnaires are readily accessible information that respondents use in the mail mode when making a decision about whether to participate again, whereas these characteristics have no effect in the web mode. In addition, privacy concerns have an impact in the web mode but not in the mail mode