The length of the retention interval, forgetting, and subjective similarity.

A long retention interval tends to result in the poor retention known as forgetting. A high subjective similarity between stimuli frequently produces their poor retention. Thus, a long retention interval may increase the subjective similarity between stimuli (the RIISS hypothesis), and this increase may produce forgetting. To examine this hypothesis, college students made speeded same-different discriminations between two lines or tones of different lengths or frequencies that were 400 ms or 3,300 ms apart, and they rated the similarity of these stimuli. The long interval produced poorer overall performance as expected, but also produced poorer performance on different than same stimuli, implying that it increased the subjective similarity between the initial and subsequent stimuli, and it also increased rated similarity, in support of the RIISS hypothesis. The position that stored stimuli lose less common information than distinctive information explains RIISS evidence better than does perturbation theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultrafast superconducting single-photon detectors for near-infrared-wavelength quantum communications

Abstract

The paper reports progress on the design and development of niobium-nitride, superconducting single-photon detectors (SSPDs) for ultrafast counting of near-infrared photons for secure quantum communications. The SSPDs operate in the quantum detection mode, based on photon-induced hotspot formation and subsequent appearance of a transient resistive barrier across an ultrathin and submicron-width superconducting stripe. The devices are fabricated from 3.5 nm thick NbN films and kept at cryogenic (liquid helium) temperatures inside a cryostat. The detector experimental quantum efficiency in the photon-counting mode reaches above 20% in the visible radiation range and up to 10% at the 1.3–1.55 μn infrared range. The dark counts are below 0.01 per second. The measured real-time counting rate is above 2 GHz and is limited by readout electronics (the intrinsic response time is below 30 ps). The SSPD jitter is below 18 ps, and the best-measured value of the noise-equivalent power (NEP) is 2 × 10^?18 W/Hz^1/2. at 1.3 μm. In terms of photon-counting efficiency and speed, these NbN SSPDs significantly outperform semiconductor avalanche photodiodes and photomultipliers.     

Primary inoperable cancer of the breast

Esophagograms of 35 patients were interpreted without knowledge of clinical history by four diagnostic radiologists. Six esophagograms were of normal esophagi, 16 were of various benign disorders, and 13 were examples of small (less than 3.5 cm) esophageal carcinomas. Overall diagnostic accuracy averaged 58%. Small esophageal carcinomas were initially diagnosed accurately in 73% of cases. Of the 27% false negative diagnoses, 6% were interpreted as normal and 21% as benign abnormalities. Esophageal lesions in the form of ulceration surrounded by mass were most often diagnosed correctly as carcinoma. The most common error was interpretation of esophagitis, stricture, and ulcerated benign lesions as carcinoma. Esophagography was found to be a good screening procedure for detection of esophageal disease but not for accurate diagnosis of small carcinomas.     

Vicarious traumatization: An empirical study of the effects of trauma work on trauma therapists.

This study examined vicarious traumatization (i.e., the deleterious effects of trauma therapy on the therapist) in 188 self-identified trauma therapists. Participants completed questionnaires about their exposure to survivor clients' trauma material as well as their own psychological well-being. Those newest to the work were experiencing the most psychological difficulties (as measured by the Traumatic Stress Institute Belief Scale; L. A. Pearlman, in press) and Symptom Checklist-90—Revised (L. Derogatis, 1977) symptoms. Trauma therapists with a personal trauma history showed more negative effects from the work than those without a personal history. Trauma work appeared to affect those without a personal trauma history in the area of other-esteem. The study indicates the need for more training in trauma therapy and more supervision and support for both newer and survivor trauma therapists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Filters and filter banks for periodic signals, the Zak transform,and fast wavelet decomposition

We present a new approach to filtering and reconstruction of periodic signals. The tool that proves to handle these tasks very efficiently is the discrete Zak transform. The discrete Zak transform can be viewed as the discrete Fourier transform performed on the signal blocks. It also can be considered the polyphase representation of periodic signals. Fast filtering-decimation-interpolation-reconstruction algorithms are developed in the Zak transform domain both for the undersampling and critical sampling cases. The technique of finding the optimal biorthogonal filter banks, i.e., those that would provide the best reconstruction even in the undersampling case, is presented. An algorithm for orthogonalization of nonorthogonal filters is developed. The condition for perfect reconstruction for the periodic signals is derived. The generalizations are made for the nonperiodic sequences, and several ways to apply the developed technique to the nonperiodic sequences are considered. Finally, the developed technique is applied to recursive filter banks and the discrete wavelet decomposition     

Non-Isothermal Cool Flames in Unstirred Static Reactors: A Compressible Model with Global Kinetics

A compressible model is developed with kinetics based on the Wang–Mou five-step global kinetic scheme and used to evaluate the temperature, concentration, and velocity fields characteristic of low-temperature combustion in unstirred static reactors. This work relaxes the assumption of small exothermicity that enabled prior studies to employ the Boussinesq approximation, valid for cases where βΔT < < 1, i.e., slow reactions and cool flames. In this study, the range of validity of the model is extended to cases with large temperature excursions, including multi-stage ignition. For the weakly exothermic cases considered, including modes of slow reaction and cool flames, the Boussinesq approximation is completely adequate. However, it overpredicts the density change and underpredicts the ignition delay time for high-temperature ignitions. Qualitative comparison with experimental results acquired at microgravity conditions are also discussed.     

Reducing intergroup prejudice and conflict: A commentary.

This commentary describes an alternative conceptual framework for interpreting the effects that E. L. Paluck (2009) found in evaluating a public education radio drama in Rwanda. The radio drama included information about the origins and impact of violence and the avenues to prevention and healing, with the aim of preventing new violence. In addition to comparing theoretical perspectives and their practical implications, the commentary addresses the spread of effect through public discussion, the program content, the participants' past experience, and measurement issues shaping the impact of the radio drama. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A new flexible bi-orthogonal filter design for multiresolutionfilterbanks with application to image compression

We propose a new fast method with great potential for multiresolution pyramid decomposition of signals and images. The method allows unusual flexibility in choosing a filter for any task involving the multiresolution analysis and synthesis. Using our method, one can choose any low-pass filter for the multiresolution filtering. This method enabled us to choose the best filters for set partitioning in hierarchical trees (SPIHT) image compression for the corresponding support sizes. The compression results for our seven tap filters are better than those of the 9/7 wavelet filters and approximately the same as those of the 10/18 filters, while at the same time our seven tap filters are faster than 10/18 filters     

Onchocerca volvulus-mediated keratitis: cytokine production by IL-4-deficient mice

Corneal inflammation similar to human onchocercal keratitis can be induced in mice by subcutaneous immunization of a soluble extract of Onchocerca volvulus (OvAg) followed by direct injection of OvAg into the corneal stroma. Previous studies have shown that corneal pathology is associated with increased systemic and corneal Th2 cytokine expression and that IL-4 gene knockout (IL-4-/-) mice develop less severe or no O. volvulus-mediated keratitis. The current study examined the contribution of Th2 cytokines to the diminished OvAg-induced corneal immunopathology observed in IL-4-/- mice. IL-4-/- mice (129Sv x C57B1/6), wild-type F2 littermates (IL-4+/+), and C57B1/6 mice were sensitized by repeated subcutaneous immunization with OvAg. Ten days after the final immunization, mice were sacrificed, spleens were removed, and cells were incubated with OvAg. Cells from immunocompetent C57B1/6 and IL-4+/+ mice produced IL-4 and IL-5, but no IFN-gamma, whereas cells from IL-4-/- mice had elevated IFN-gamma and no IL-4. Interestingly, cells from these animals produced levels of IL-5 protein equivalent to those of C57B1/6 and IL-4+/+ mice. To determine cytokine production in corneas during the onset of onchocercal keratitis, OvAg-immunized mice were injected intracorneally with OvAg, and cytokine gene expression in the cornea was determined by RT-PCR. Temporal analysis of cytokine gene expression in corneas of immunocompetent mice showed that the Th2-associated cytokines IL-4, IL-5, IL-10, and IL-13 were produced within 1 day of intrastromal injection, with sustained elevations for 10 days. Maximal IFN-gamma mRNA levels were not detected until Day 10. This was in contrast to IL-4-/- mice in which IFN-gamma appeared at Day 1 and remained elevated for at least 10 days. Moreover, in corneas from IL-4-/- mice, all Th2 cytokines with the exception of IL-4 were up-regulated and expressed with kinetics similar to that of IL-4+/+ littermates. Histologically, corneas from IL-4-/- mice were less edematous and contained fewer eosinophils and other inflammatory cells than those from immunocompetent controls. As there was no difference in peripheral eosinophil levels, these data indicate that the diminished severity of onchocercal keratitis in IL-4-/- mice is not due to failure to develop systemic or local Th2 cytokine responses or to produce eosinophils, but that IL-4 may be involved in recruitment of eosinophils and other inflammatory cells into the corneal stroma.