Online pairing of VoIP conversations

This paper answers the following question; given a multiplicity of evolving 1-way conversations, can a machine or an algorithm discern the conversational pairs in an online fashion, without understanding the content of the communications? Our analysis indicates that this is possible, and can be achieved just by exploiting the temporal dynamics inherent in a conversation. We also show that our findings are applicable for anonymous and encrypted conversations over VoIP networks. We achieve this by exploiting the aperiodic inter-departure time of VoIP packets, hence trivializing each VoIP stream into a binary time-series, indicating the voice activity of each stream. We propose effective techniques that progressively pair conversing parties with high accuracy and in a limited amount of time. Our findings are verified empirically on a dataset consisting of 1,000 conversations. We obtain very high pairing accuracy that reaches 97% after 5 min of voice conversations. Using a modeling approach we also demonstrate analytically that our result can be extended over an unlimited number of conversations.     

Structure-function studies of an IGF-I analogue that can be chemically cleaved to a two-chain mini-IGF-I

The structure and biological activities of two disulphide isomersof a C-region deletion mutant of insulin-like growth factor-I(IGF-I) which has an Asn–Gly link engineered at the junctionof the A- and B-regions were studied before and after chemicalcleavage. Circular dichroism (CD) spectra and binding affinityto IGF binding protein 3 (IGFBP3) indicated that the treatmentwith hydroxylamine did not disrupt the overall tertiary foldof the hormones. Cleavage restored some binding affinity forthe IGF-I receptor in both isomers and weakly restored the abilityto stimulate incorporation of tritiated thymidine into DNA inNIH 3T3 fibroblasts transfected with the human IGF-I receptor.Cleavage also restored metabolic capacity, as measured by theability of the isomers to promote lipogenesis in isolated ratadipocytes through the insulin receptor. These results are consistentwith the theory that binding of IGF-I to the IGF-I receptorrequires a conformational change similar to that involved ininsulin binding the insulin receptor. The weak affinity forthe IGF-I receptor after cleavage is consistent with the beliefthat residues in the C-region interact with the IGF-I receptor.This structural difference between insulin and IGF-I gives eacha higher binding affinity for its own receptor.     

Compressive response of multilayered pyramidal lattices during underwater shock loading

The quasi-static and dynamic compressive mechanical response of a multilayered pyramidal lattice structure constructed from stainless-steel was investigated. The lattices were fabricated by folding perforated 304 stainless steel sheets and bonding them to thin intervening sheets using a transient liquid-phase bonding technique. The resulting structure was attached to thick face sheets and the through thickness mechanical response was investigated quasi-statically and dynamically, in the latter case using a planar explosive loading technique. The lattice is found to crush in a progressive manner by the sequential (cooperative) buckling of truss layers. This results in a quasi-static stress strain response that exhibits a significant “metal foam” like stress plateau to strains of about 60% before rapid hardening due to truss impingement with the intermediate face sheets. During dynamic loading, sequential buckling of the truss layers was manifested as a series of transmitted pressure pulses measured at the back face of the test samples. The sequential buckling extended the duration of the back face pressure–time waveform and significantly reduced the transmitted pressure measured at the back face. The impulse transmitted to the structure is found to be about 28% less than that predicted by analytic treatments of the fluid-structure interaction for fully supported structures. This transmitted impulse reduction appears to be a consequence of the wet side face sheet movement away from the blast wave and is facilitated by the low crush resistance of the lattice structure.     

Does the use of telemental health alter the treatment experience? Inmates' perceptions of telemental health versus face-to-face treatment modalities.

In corrections, where staffing limitations tax an overburdened mental health system, telemental health is an increasingly common mode of mental health service delivery. Although telemental health presents an efficient treatment modality for a spectrum of mental health services, it is imperative to study how this modality influences key elements of the treatment experience. In this study, the authors compared inmates' perceptions of the working alliance, postsession mood, and satisfaction with psychiatric and psychological mental health services delivered through 2 different modalities: telemental health and face-to-face. Participants consisted of 186 inmates who received mental health services (36 via telepsychology, 50 via face-to-face psychology, 50 via telepsychiatry, and 50 via face-to-face psychiatry). Results indicate no significant differences in inmates' perceptions of the work alliance with the mental health professional, postsession mood, or overall satisfaction with services when telemental health and face-to-face modalities were compared within each type of mental health service. Implications of these findings are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time to stop researching the important things?

From 2010 government funding for UK research will be based partly on metrics. One of the key metrics will be citations, with research income and postgraduate student numbers also assessed. While citation metrics seem sensible, there is a serious issue of what topics one researches, the methods used and the way in which a move to the use of citations will induce a change in research behaviour – especially a move to the dull middle ground. This paper investigates the potential impact of such a move on niche areas of IS research – here research on small- and medium-sized enterprises. However, the arguments hold for any new, emerging, or non-mainstream research area. The impacts of citation metrics on publication outlets and research method choice are assessed.     

Modelling of alcohol and water diffusion in fuel cell membranes—Experimental validation by means of in situ Raman spectroscopy

In this work a multi-component transport model has been set up to describe the diffusion driven mass transport of water and methanol in fuel cell membranes. For a membrane in contact with liquid methanol and water on one side and conditioned air on the other, the corresponding differential equations and boundary conditions were derived in a polymer-related coordinate system taking into account the polymers three-dimensional swelling. Phase equilibrium parameters and unknown diffusion coefficients for Nafion^® 117 were obtained by comparing the simulation results to water and methanol concentration profiles measured with confocal Raman spectroscopy. The influence of methanol concentration, temperature and air flow rate was predicted by the model with a maximum relative mean deviation between measurement and simulation of 8.6% for methanol and 3.4% for water.     

Transient frequency shift in a single-mode quasi-continuousdiode-pumped Nd:YAG laser

The transient frequency shift of a quasi-continuous single-mode frequency-doubled diode-pumped Nd:YAG ring laser has been measured using a confocal spherical Fabry-Perot. At a rate of 50 Hz, a quasi-linear shift of 5.4 MHz at the fundamental 1.06-μm wavelength has been measured during the 150-μs laser pulse duration. The doubled frequency, which is obtained by an intracavity LBO crystal, shows also a similar but doubled linear shift. This observed frequency shift is interpreted as due to thermal effects in the rod and fits well a modeling of the pulsed laser diode pumping. Introducing intracavity compensation, a piezoceramic transducer mounted cavity mirror, has limited the observed shift to less than ±1 MHz. Such a quasi-continuous Nd:YAG single-mode and frequency stabilized device should be a very suitable single-mode laser source to pump optical parametric oscillator systems     

Contextual insensitivity in schizophrenic language processing: Evidence from lexical ambiguity.

The authors investigated whether contextual failures in schizophrenia are due to deficits in the detection of context or the inhibition of contextually irrelevant information. Eighteen schizophrenia patients and 24 nonpsychiatric controls were tested via a cross-modal semantic priming task. Participants heard sentences containing homonyms and made lexical decisions about visual targets related to the homonyms' dominant or subordinate meanings. When sentences moderately biased subordinate meanings (e.g., the animal enclosure meaning of pen), schizophrenia patients showed priming of dominant targets (e.g., paper) and subordinate targets (e.g., pig). In contrast, controls showed priming only of subordininate targets. When contexts strongly biased subordinate meanings, both groups showed priming only of subordinate targets. The results suggest that inhibitory deficits rather than context detection deficits underlie contextual failures in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distinguishing conscious from unconscious perceptual processes.

Discusses the relationship between perceptual processing and awareness, based on a distinction between subjective and objective recognition thresholds. To test the proposed theoretical position that, since perceptual awareness is a subjective state, the subjective (for claimed awareness) threshold better captures the phenomenological distinction between conscious and unconscious processes than the objective threshold (based on discriminative responding), 3 experiments were conducted. The 3rd experiment provided, under slightly different conditions, empirical support for the findings of the 1st two. Exps I and II (with 16 college students and 16 19–29 yr old adults, respectively) used a Stroop-priming task. Results indicate that masked color words, presented above and below a subjective threshold, were effective primes for the subsequent naming of color patches and that the primes had qualitatively different effects. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)