3,280 research outputs found

    Investigations into the occurrence and causes of diel changes in the chemistry of streams

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    Bounds on higher-order Lorentz-violating photon sector coefficients from an asymmetric optical ring resonator experiment

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    Optical resonators provide a powerful tool for testing aspects of Lorentz invariance. Here, we present a reanalysis of an experiment where a path asymmetry was created in an optical ring resonator by introducing a dielectric prism in one arm. The frequency difference of the two fundamental counter-propagating modes was then recorded as the apparatus was orientation-modulated in the laboratory. By assuming that the minimal Standard-Model Extension coefficients vanish we are able to place bounds on higher-order parity-odd Lorentz-violating coefficients of the Standard-Model Extension. The results presented in this work set the first constraints on two previously unbounded linear combinations of d=8 parity-odd nonbirefringent nondispersive coefficients of the photon sector.Comment: 6 pages, 4 figures, 3 tables, accepted for publication in Physics Letters

    Cross-correlation measurement techniques for cavity-based axion and weakly interacting slim particle searches

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    The search for dark matter is of fundamental importance to our understanding of the universe. Weakly-Interacting Slim Particles (WISPs) such as axions and hidden sector photons (HSPs) are well motivated candidates for the dark matter. Some of the most sensitive and mature experiments to detect WISPs rely on microwave cavities, and the detection of weak photon signals. It is often suggested to power combine multiple cavities, which creates a host of technical concerns. We outline a scheme based on cross-correlation for effectively power combining cavities and increasing the signal-to-noise ratio of a candidate WISP signal.Comment: 8 pages, 9 figure

    Enriching the Historiography of Religious Education: Insights from Oral Life History

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    This article seeks to exemplify the extent to which oral life history research can enrich existing historiographies of English Religious Education (RE). Findings are reported from interviews undertaken with a sample of key informants involved in designing and/or implementing significant curriculum changes in RE in the 1960s and 1970s. The interviews provided insights into personal narratives and biographies that have been marginal to, or excluded from, the historical record. Thematic analysis of the oral life histories opened a window into the world of RE, specifically in relation to professional identity and practice, curriculum development, and professional organizations, thereby exposing the operational dynamics of RE at an (inter-)personal and organizational level. The findings are framed by a series of methodological reflections. Overall, oral life histories are shown to be capable of revealing that which was previously hidden and which can be confirmed and contrasted with knowledge gleaned from primary documentary sources

    Determinant criteria in the ocean carrier selection process

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    This study examines key determinant criteria used by import and export shippers when selecting an international containership carrier. A sample of import and export shippers were asked to evaluate eighteen service characteristics based on whether or not the characteristics were required by their international containership carriers. The results of Pearson chi-square tests indicate a significant difference between import shippers and export shippers on three of the eighteen service characteristics. Import shippers were more demanding of their carriers by requiring door-to-door transportation rates, shipment expediting, and shipment tracing services

    Curvilinear ridges and related features in southwest Cydonia Mensae, Mars

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    Examined is a region on Mars in southwest Cydonia Mensae (32 deg lat., 17 deg long.) just northwest of the lowland/upland boundary escarpment. The dominant morphological features in this region are the clusters of large massifs and plateau outliers (PI), knobby material (K), and smooth lowland plains (Ps). Surrounding the clusters and linking many isolated knobs is a system of curvilinear ridges and arcuate terrain boundaries which tend to separate the massifs and knobs from the smooth plains. Curvilinear ridges are arcuate to nearly linear and smoother in plan than wrinkle ridges and show no apparent correlation with regional structural grain. They are typically 5 to 10 km long but can range from as little as 2 or 3 km to greater than 50 km long. The widths vary from about 100 m to as much as 2 km. Curvilinear ridges are most numerous within 100 km of the lowland/upland boundary escarpment and are associated with massifs and knobby terrain. Arcuate terrain boundaries appear between units of different apparent albedo or arcuate breaks in slope

    Geomorphic evidence for ancient seas in west Deuteronilus Mensae, Mars-2: From very high resolution Viking Orbiter images

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    Very high resolution Viking Orbiter images of the Martian surface, though rare, make it possible to examine specific areas at image scales approaching those of high altitude terrestrial aerial photographs. Twenty three clear images lie within west Deuteronilus Mensae. The northernmost images which constitute an almost unbroken mosaic of the west wall of a long fingerlike canyon are examined. Morphological details on the plateau surface within zone B, not detectable at low resolution, make it possible to divide the zone into two distinct subzones separated by an east-west escarpment. The morphology of the canyon floor is described in detail
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