11,042 research outputs found

    The Historical Development of Easter-Southern Freight Rate Relationships

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    A method for creating and presenting video-recorded synchronized audiovisual stimuli at a high frame rate-which would be highly useful for psychophysical studies on, for example, just-noticeable differences and gating-is presented. Methods for accomplishing this include recording audio and video separately using an exact synchronization signal, editing the recordings and finding exact synchronization points, and presenting the synchronized audiovisual stimuli with a desired frame rate on a cathode ray tube display using MATLAB and Psychophysics Toolbox 3. The methods from an empirical gating study (Moradi, Lidestam, and Ronnberg, Frontiers in Psychology 4: 359, 2013) are presented as an example of the implementation of playback at 120 fps

    Simultaneous optical polarimetry and X-ray observations of the magnetic CV CP Tuc (AX J2315--592)

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    CP Tuc (AX J2315--592) shows a dip in X-rays which lasts for approximately half the binary orbit and is deeper in soft X-rays compared with hard X-rays. It has been proposed that this dip is due to the accretion stream obscuring the accretion region from view. If CP Tuc was a polar, as has been suggested, then the length of such a dip would make it unique amongst polars since in those polars in which a dip is seen in hard X-rays the dip lasts for only 0.1 of the orbit. We present optical polarimetry and RXTE observations of CP Tuc which show circular polarisation levels of ~10 per cent and find evidence for only one photometric period. These data confirm CP Tuc as a polar. Our modelling of the polarisation data imply that the X-ray dip is due to the bulk of the primary accretion region being self-eclipsed by the white dwarf. The energy dependence of the dip is due to a combination of this self-eclipse and also the presence of an X-ray temperature gradient over the primary accretion region.Comment: 6 pages, accepted for publication in MNRA

    Литературные тексты и римские историки

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    В монографии освещаются проблемы и методы историко-филологической реконструкции античной истории. Автор исследует разные виды текстов и те способы, посредством которых древние авторы воссоздавали историю Рима. В монографии представлены и альтернативные формы нарративной традиции, а также рецепция античной историографии в исторической науке конца XX в.Настоящая монография издана в серии "Approaching the Ancient World". Приложения: каталог античных авторов, представленных в книге, и международные издания их трудов (с. 156-167), избранная библиография (с. 203-211), общий указатель (с. 212-218)

    Quasi-optical antenna-mixer-array design for terahertz frequencies

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    A new quasi-optical antenna-mixer-array design for terahertz frequencies is presented. In the design, antenna and mixer are combined into an entity, based on the technology in which millimeter-wave horn antenna arrays have been fabricated in silicon wafers. It consists of a set of forward- and backward-looking horns made with a set of silicon wafers. The front side is used to receive incoming signal, and the back side is used to feed local oscillator signal. Intermediate frequency is led out from the side of the array. Signal received by the horn array is picked up by antenna probes suspended on thin silicon-oxynitride membranes inside the horns. Mixer diodes will be located on the membranes inside the horns. Modeling of such an antenna-mixer-array design is done on a scaled model at microwave frequencies. The impedance matching, RF and LO isolation, and patterns of the array have been tested and analyzed

    Discovery of spin modulated circular polarization from IGR J17014-4306, the remnant of Nova Scorpii 1437 A.D

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    Polarimetry of IGR J1401-4306, a long period (12.7 hours), eclipsing intermediate polar and remnant of Nova Scorpii 1437 A.D., reveals periodic variations of optical circular polarization, confirming the system as the longest period eclipsing intermediate polar known. This makes it an interesting system from an evolutionary perspective. The circular polarization is interpreted as optical cyclotron emission from an accreting magnetic white dwarf primary. Based on the polarimetry, we propose that it is a disc-fed intermediate polar. The detection of predominantly negative circular polarization is consistent with only one of the magnetic poles dominating the polarized emission, while the other is mostly obscured by the accretion disc.Comment: 7 pages, figures, accepted for publication in MNRA

    Probe modeling for millimeter-wave integrated-circuit horn antennas

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    Integrated-circuit probe-excited horn-antenna arrays etched in silicon are well developed. They are a very promising class of antenna arrays for milli-meter and submillimeter applications. Further development of this technology involves integrating mixers and amplifiers into the antenna arrays. In an effort to develop an antenna-mixer array based on the existing technology, various antenna probes inside the pyramidal horns have been examined on scaled model-horns at the microwave frequencies. In this paper, modeling results and design principles of these antenna probes have been presented, which include the resonant impedance, the operating frequency, and the bandwidth of the horn antennas. These measurement results provide a guideline in designing probes for millimeter/submillimeter-wave integrated-circuit horn-antenna-mixer arrays
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