The psychophysics of absolute threshold and signal duration: A probabilistic approach

The absolute threshold for a tone depends on its duration; longer tones have lower thresholds. This effect has traditionally been explained in terms of ?temporal integration? involving the summation of energy or perceptual information over time. An alternative probabilistic explanation of the process is formulated in terms of simple equations that predict not only the time=duration dependence but also the shape of the psychometric function at absolute threshold. It also predicts a tight relationship between these two functions. Measurements made using listeners with either normal or impaired hearing show that the probabilistic equations adequately fit observed threshold-duration functions and psychometric functions. The mathematical formulation implies that absolute threshold can be construed as a two-valued function: (a) gain and (b) sensory threshold, and both parameters can be estimated from threshold-duration data. Sensorineural hearing impairment is sometimes associated with a smaller threshold=duration effect and sometimes with steeper psychometric functions. The equations explain why these two effects are expected to be linked. The probabilistic approach has the potential to discriminate between hearing deficits involving gain reduction and those resulting from a raised sensory threshold

Polymer-based electrospray chips for mass spectrometry

In this paper, we present our development of a MEMS chip with an overhanging polymer microcapillary 2.5 mm in length and with a 5 µm x 10 µm orifice size at the tip. The fabricated chips have been successfully interfaced with a mass spectrometer (MS) to validate electrospray ionization (ESI) for biochemical analysis. The prediction of a reduction in Taylor cone size has also been observed with real time ESI fluid visualization from our chip. Built-in micro particle filters and centimeter long serpentine microchannels were fabricated on the chip with a low temperature process by using the Parylene polymer as a structural material, aluminum and photoresist as sacrificial layers, and bromine trifluoride (BrF_3) gas phase etching for final microcapillary releasing. The use of an overhanging polymer structure adds a new a level of mechanical robustness that was never achievable with other thin films. Functionality of our device was proven by consistent detection of myoglobin in a 200 nM solution at a flow rate of 35 nL/min and a voltage potential of 1.5 kV. This MS interface chip represents vital and significant improvements in MEMS process technology and MS functionality with respect to the silicon nitride (Si_xN_y) ESI nozzles previously reported

Model driven formal development of digital libraries

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-540-68262-2_13Revised Selected Papers of the Third International Conference, WEBIST 2007, Barcelona, Spain, March 3-6, 2007This paper shows our model-driven approach for the formal construction and validation of Digital Libraries (DLs). We have defined a Domain Specific Visual Language (DSVL) called VisMODLE, which allows the description of a DL using five different viewpoints: services, behaviour, collections, structure and society. From a meta-model based description of the different viewpoints, we have generated a modelling environment for VisMODLE. We have provided the environment with a code generator that produces XUL code for the DL’s user interface and composes the application using predefined components that implement the different services. Moreover, we have also added validation and simulation capabilities to the environment. Using the behavioural models (state-machine based), we can visually animate the system. In addition, the combined behaviour of actors and services can be transformed into a Petri net for further analysis.Work sponsored by projects MODUWEB (TIN2006-09678) and MOSAIC (TIC2005-08225-C07-06) of the Spanish Ministry of Science and Educatio

Examination of a site-based peer coaching inservice model

The major purpose of this exploratory study was to examine the effects of a site-based, peer coaching inservice model. A single-group, interrupted time-series design was utilized. The data were gathered from eleven teachers from two secondary schools in central Iowa during the 1984-85 school year. The treatment was a structured inservice training unit focusing on teacher questioning strategies using peer coaching to enhance teacher effectiveness;Principals from both schools received training on questioning strategies and peer coaching before conducting building-level inservice for teachers. After the workshop, teachers practiced questioning skills in their classrooms while coaching each other. The data for the study were gathered from audio-tapes of classroom lessons and self-reports of teacher\u27s perceptions of their experiences. Questions from each audio-taped lesson were rated for effective use of ten questioning strategies. Teachers\u27 perceptions were reported via structured interviews after the study;Findings supported the use of the model for delivery and use of inservice training. Teachers increased their questioning effectiveness after the treatment with most improvement in using wait-time and probing for clarification. Teachers reported their improvement was most influenced by practicing, observing colleagues, and receiving feedback. Teachers preferred this approach to inservice training over their experiences with a more typical approach--presentation of theory. Teachers reported being more positive about aspects of collegial relations and professional growth after their participation in the activities of the model. Of ten teachers interviewed, nine said they would choose to participate in a similar approach to inservice if given the opportunity;The Site-based, Peer Coaching (SBPC) inservice model showed promise for training teachers. Teachers not only increased their questioning effectiveness in their classrooms, but they preferred the SBPC approach to inservice training. Teachers rated the components of the model that comprise peer coaching most influential in their improvement and reported that the activities may have positively affected their perceptions of collegial relations and professional growth. Inservice training conducted by the building principal followed by practice and peer coaching was an effective way of increasing teachers\u27 effectiveness

A Meta-Analysis of the Antecedents of Voluntary Turnover in Studies Involving Active Duty Military Member Populations

Studies have explored the antecedents to turnover in the military; however, results vary. This research used a meta-analytic method to evaluate reported correlations between antecedents of turnover intent and turnover in an effort to understand the true relationship between them and offer insight to leaders as to where they can affect turnover within their organizations. Included studies reported a military sample and were published between 1973 and 2009. The meta-analysis revealed no correlation between OPTEMPO and turnover intent. Not enough studies were included to evaluate the relationship between OPTEMPO and turnover. Varying definitions and measurements of OPTEMPO raised concern. Additional primary research is needed with consistent definition and measurement of OPTEMPO. This study did validate that turnover intent and turnover had the strongest positive relationship with an 80% credibility range of 0.43 to 0.58. Organizational commitment and turnover had the strongest negative relationship with an 80% credibility range of -0.49 to -0.34. For the dependent variable turnover intent, job search had the strongest positive relationship with an 80% credibility range of 0.41 to 0.56. Organizational commitment also had the strongest negative relationship with turnover intent. The 80% credibility interval was -0.65 to -0.50. Leaders should focus their efforts on organizational commitment to influence subordinates’ turnover decisions

Importance of spike timing in touch: an analogy with hearing?

Touch is often conceived as a spatial sense akin to vision. However, touch also involves the transduction and processing of signals that vary rapidly over time, inviting comparisons with hearing. In both sensory systems, first order afferents produce spiking responses that are temporally precise and the timing of their responses carries stimulus information. The precision and informativeness of spike timing in the two systems invites the possibility that both implement similar mechanisms to extract behaviorally relevant information from these precisely timed responses. Here, we explore the putative roles of spike timing in touch and hearing and discuss common mechanisms that may be involved in processing temporal spiking patterns

Becoming Responsible Learners: Community Matters

Students at Iowa State University had the opportunity to enroll in a two-year National Science Foundation (NFS) Scholarship for Service (SFS) leadership development program, in addition to their work within their majors. This interdisciplinary program included faculty and students in computer engineering, computer science, mathematics, political science, management information systems, and education. The expected learning outcomes for this interdisciplinary effort were focused on “learning in community,” specifically to develop professionals and citizens who will continue learning for life while consistently supporting and encouraging the growth of others. The purpose of this phenomenological research study was to examine students’ experiences of learning in community in the SFS program. Participants identified a definable developmental process where students’ experiences moved from resistance to the interactive and participatory nature of the class, to reluctance to step outside comfort zones, to reliance on others within the community, to assuming responsibility for self and others in the community

Congenital amusics use a secondary pitch mechanism to identify lexical tones

Amusia is a pitch perception disorder associated with deficits in processing and production of both musical and lexical tones, which previous reports have suggested may be constrained to fine-grained pitch judgements. In the present study speakers of tone-languages, in which lexical tones are used to convey meaning, identified words present in chimera stimuli containing conflicting pitch-cues in the temporal fine-structure and temporal envelope, and which therefore conveyed two distinct utterances. Amusics were found to be more likely than controls to judge the word according to the envelope pitch-cues. This demonstrates that amusia is not associated with fine-grained pitch judgements alone, and is consistent with there being two distinct pitch mechanisms and with amusics having an atypical reliance on a secondary mechanism based upon envelope cues