434 research outputs found

    Effects of aircraft noise on human activities

    Get PDF
    The effects of aircrft noise on human activities was investigated by developing a battery of tasks (1) representative of a range of human activities and (2) sensitive to the disruptive effects of noise. The noise used were recordings of jet aircraft and helicopter sounds at three lvels of loudness--60, 70, and 80 dB(A). Experiment 1 investigated 12 different cognitive tasks, along with two intelligibility tasks included to validate that the noises were being effective. Interference with intelligibility was essentially the same as found in the research literature, but only inconsistent effects were found on either accuracy or latency of performance on the cognitive tasks. When the tasks were grouped into four categories (Intelligibility, Matching, Verbal, and Arithmetic), reliable differences in rated annoyingness of the noises were related to the task category and to the type of noise (jet or helicopter)

    Fractionation of distance in simulated space

    Get PDF
    Fractionation of distance in space environment simulatio

    Magnitude estimation of perceived distance over various distance ranges

    Get PDF
    Magnitude estimation judgments of perceived distance for stationary space vehicle under conditions simulating outer spac

    Verbal estimation of distance in a simulated space environment

    Get PDF
    Human performance in estimating distances in simulated space environmen

    p-Type doping of II-VI heterostructures from surface states: application to ferromagnetic Cd1x_{1-x}Mnx_xTe quantum wells

    Full text link
    We present a study of p-type doping of CdTe and Cd1x_{1-x}Mnx_xTe quantum wells from surface states. We show that this method is as efficient as usual modulation doping with nitrogen acceptors, and leads to hole densities exceeding 2×10112 \times 10^{11} cm2^{-2}. Surface doping was successfully applied to obtain carrier-induced ferromagnetism in a Cd1x_{1-x}Mnx_xTe quantum well. The observed temperature dependence of photoluminescence spectra, and the critical temperature, correspond well to those previously reported for ferromagnetic quantum wells doped with nitrogen.Comment: 4 figure

    Distance discrimination in a simulated space environment

    Get PDF
    Successive comparisons method used for distance discrimination tests in simulated space environmen

    Light and electric field control of ferromagnetism in magnetic quantum structures

    Full text link
    A strong influence of illumination and electric bias on the Curie temperature and saturation value of the magnetization is demonstrated for semiconductor structures containing a modulation-doped p-type Cd0.96Mn0.04Te quantum well placed in various built-in electric fields. It is shown that both light beam and bias voltage generate an isothermal and reversible cross-over between the paramagnetic and ferromagnetic phases, in the way that is predetermined by the structure design. The observed behavior is in quantitative agreement with the expectations for systems, in which ferromagnetic interactions are mediated by the weakly disordered two-dimensional hole liquid.Comment: 4 pages and 3 figure

    pH-Dependent behaviour of soluble protein aggregates formed during heat-treatment of milk at pH 6.5 or 7.2

    Get PDF
    Soluble (SA) and micelle-bound (MA) protein aggregatesformed during the heat-treatment of milk are thought toincrease the gelation pH and gel strength of acid milk gels.The ratio SA/MA increases as heat-treatment pH is increased and the resulting gels are stronger. The objective was to study the pH-dependent behaviour of SA produced by heattreatment at pH 6.5 (SA6.5) and 7.2 (SA7.2) in order to get a better understanding of their role in acid gelation of heated skim milk

    Optical frequency measurement of the 1S-3S two-photon transition in hydrogen

    Full text link
    This article reports the first optical frequency measurement of the 1S3S1\mathrm{S}-3\mathrm{S} transition in hydrogen. The excitation of this transition occurs at a wavelength of 205 nm which is obtained with two frequency doubling stages of a titanium sapphire laser at 820 nm. Its frequency is measured with an optical frequency comb. The second-order Doppler effect is evaluated from the observation of the motional Stark effect due to a transverse magnetic field perpendicular to the atomic beam. The measured value of the 1S1/2(F=1)3S1/2(F=1)1\mathrm{S}_{1/2}(F=1)-3\mathrm{S}_{1/2}(F=1) frequency splitting is 2922742936.729(13)MHz2 922 742 936.729 (13) \mathrm{MHz} with a relative uncertainty of 4.5×10124.5\times10^{-12}. After the measurement of the 1S2S1\mathrm{S}-2\mathrm{S} frequency, this result is the most precise of the optical frequencies in hydrogen

    Block of death-receptor apoptosis protects mouse cytomegalovirus from macrophages and is a determinant of virulence in immunodeficient hosts.

    Get PDF
    The inhibition of death-receptor apoptosis is a conserved viral function. The murine cytomegalovirus (MCMV) gene M36 is a sequence and functional homologue of the human cytomegalovirus gene UL36, and it encodes an inhibitor of apoptosis that binds to caspase-8, blocks downstream signaling and thus contributes to viral fitness in macrophages and in vivo. Here we show a direct link between the inability of mutants lacking the M36 gene (ΔM36) to inhibit apoptosis, poor viral growth in macrophage cell cultures and viral in vivo fitness and virulence. ΔM36 grew poorly in RAG1 knockout mice and in RAG/IL-2-receptor common gamma chain double knockout mice (RAGγC(-/-)), but the depletion of macrophages in either mouse strain rescued the growth of ΔM36 to almost wild-type levels. This was consistent with the observation that activated macrophages were sufficient to impair ΔM36 growth in vitro. Namely, spiking fibroblast cell cultures with activated macrophages had a suppressive effect on ΔM36 growth, which could be reverted by z-VAD-fmk, a chemical apoptosis inhibitor. TNFα from activated macrophages synergized with IFNγ in target cells to inhibit ΔM36 growth. Hence, our data show that poor ΔM36 growth in macrophages does not reflect a defect in tropism, but rather a defect in the suppression of antiviral mediators secreted by macrophages. To the best of our knowledge, this shows for the first time an immune evasion mechanism that protects MCMV selectively from the antiviral activity of macrophages, and thus critically contributes to viral pathogenicity in the immunocompromised host devoid of the adaptive immune system
    corecore