1,066 research outputs found

    Rate-Distortion Efficient Amplitude Modulated Sinusoidal Audio Coding

    Get PDF

    On the Structure of ZnI2{\rm ZnI_2}

    Full text link
    A new structure for ZnI2{\rm ZnI_2} is proposed which it exists in tetragonal state. In this structure the ZnI2{\rm ZnI_2} molecule exists in a nonlinear array and forms the basis of the tetragonal unit cell with one basis per unit cell. The structural analysis based on the reflections listed in ASTM 30-1479 shows that the proposed structure is correct.Comment: six pages and four figures. Manuscript prepared in RevTe

    Multiband Amplitude Modulated Sinusoidal Audio Modeling

    Get PDF

    A novel route to phase formation of cobalt oxyhydrates using KMnO4 as an oxidizing agent

    Full text link
    We have first succeefully synthesized the sodium cobalt oxyhydrate superconductors using KMnO4 as a de-intercalating and oxidizing agent. It is a novel route to form the superconductive phase of NaxCoO2.yH2O without resorting to the commonly used Br2/CH3CN solution. The role of the KMnO4 is to de-intercalate the Na+ from the parent compound Na0.7CoO2 and oxidize the Co ion as a result. The higher molar ratio of KMnO4 relative to the sodium content tends to remove more Na+ from the parent compound and results in a slight expansion of the c-axis in the unit cell. The superconducting transition temperature is 4.6-3.8 K for samples treated by the aqueous KMnO4 solution with the molar ratio of KMnO4 relative to the sodium content in the range of 0.3 and 2.29.Comment: 10 pages, 3 figure

    Performance of horn-coupled transition edge sensors for L- and S-band optical detection on the SAFARI instrument

    Get PDF
    We describe the geometry, architecture, dark- and optical performance of ultra-low-noise transition edge sensors as THz detectors for the SAFARI instrument. The TESs are fabricated from superconducting Mo/Au bilayers coupled to impedance-matched superconducting ß-phase Ta thin-film absorbers. The detectors have phonon-limited dark noise equivalent powers of order 0.5 - 1.0 aW/Hz\sqrt{Hz} and saturation powers of order 20 - 40 fW. The low temperature test configuration incorporating micro-machined backshorts is also described, and construction and typical performance characteristics for the optical load are shown. We report preliminary measurements of the optical performance of these TESs for two SAFARI bands; L-band at 110 - 210 µm and S-band 34 - 60 µm .European Space AgencyThis is the final version of the article. It first appeared from SPIE via http://dx.doi.org/10.1117/12.223274

    A Time-Domain Binaural Signal Detection Model and its Predictions for Temporal Resolution Data

    Get PDF
    Summary This paper discusses the application of a time-domain binaural signal-detection model in the context of estimates of the temporal resolution of the binaural auditory system. It is demonstrated that the optimal detector which is present in the model is crucial to account for specific temporal detection phenomena. In particular, the model can account for the apparent differences in the estimates of binaural time constants found with different experimental paradigms. It is argued that the differences in temporal-window estimates stem from listeners ability to listen off-time, whenever this enhances detection performance

    Visualizing internetworked argumentation

    Get PDF
    In this chapter, we outline a project which traces its source of inspiration back to the grand visions of Vannevar Bush (scholarly trails of linked concepts), Doug Engelbart (highly interactive intellectual tools, particularly for argumentation), and Ted Nelson (large scale internet publishing with recognised intellectual property). In essence, we are tackling the age-old question of how to organise distributed, collective knowledge. Specifically, we pose the following question as a foil: In 2010, will scholarly knowledge still be published solely in prose, or can we imagine a complementary infrastructure that is ‘native’ to the emerging semantic, collaborative web, enabling more effective dissemination and analysis of ideas

    Cyclooxygenase-2 expression and recurrence of colorectal adenomas: effect of aspirin chemoprevention

    Get PDF
    Background Low-dose aspirin reduces the incidence of colorectal cancer and recurrence of adenomas. Cyclooxygenase-2 (COX-2), one of its main target enzymes, is reportedly over-expressed in colorectal adenomas.Aim To assess COX-2 expression, in relation to adenoma recurrence and the protective effect of aspirin, in a large series of colorectal adenomas, recruited from a double-blind randomised controlled trial comparing recurrences after low-dose aspirin or placebo. Methods Follow-up colonoscopies were performed after 1 and 4 years to assess adenoma recurrence. COX-2 expression was assessed by immunohistochemistry for each adenoma obtained at baseline colonoscopy, separately for epithelium, deep stroma and overall. Architecture, grade of dysplasia, K-ras mutation, p53 and cyclin D1 expression were studied. Results COX-2 expression could be assessed in 219 adenomas from 136 patients: 128 adenomas (58%) from 59 patients strongly expressed COX-2. Strong COX-2 expression predominated in adenomas larger than 10 mm (84/129 vs 44/90; p=0.02) and in adenomas showing high-grade dysplasia (22/29 vs 104/188; p=0.04). Deep stromal but not epithelial initial expression of COX-2 predicted adenoma recurrence in the whole population (30/72 patients or 42% strongly expressed deep stromal COX-2 compared with16/64 or 25% without recurrent adenoma; p=0.04). The protective effect of aspirin was mainly observed in patients in whom COX-2 initial expression was low (RR for recurrence in patients taking aspirin with low COX-2 expression: 0.59; 95% CI 0.39 to 0.90; p=0.02). There was no significant effect of aspirin at the end of the trial. Conclusion Over-expression of COX-2 was frequent and predominated in large and high-grade dysplasia adenomas. Deep stromal but not epithelial initial expression of COX-2 predicted recurrence of adenomas. Aspirin did not act preferentially on patients whose initial adenomas strongly expressed COX-2
    • …
    corecore