2,565 research outputs found

    Vector Reflectometry in a Beam Waveguide

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    We present a one-port calibration technique for characterization of beam waveguide components with a vector network analyzer. This technique involves using a set of known delays to separate the responses of the instrument and the device under test. We demonstrate this technique by measuring the reflected performance of a millimeter-wave variable-delay polarization modulator

    Noisy Preprocessing and the Distillation of Private States

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    We provide a simple security proof for prepare & measure quantum key distribution protocols employing noisy processing and one-way postprocessing of the key. This is achieved by showing that the security of such a protocol is equivalent to that of an associated key distribution protocol in which, instead of the usual maximally-entangled states, a more general {\em private state} is distilled. Besides a more general target state, the usual entanglement distillation tools are employed (in particular, Calderbank-Shor-Steane (CSS)-like codes), with the crucial difference that noisy processing allows some phase errors to be left uncorrected without compromising the privacy of the key.Comment: 4 pages, to appear in Physical Review Letters. Extensively rewritten, with a more detailed discussion of coherent --> iid reductio

    Ethical ecosurveillance: Mitigating the potential impacts on humans of widespread environmental monitoring

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    Ecosurveillance has proliferated in recent years, generating vast amounts of data on the natural environment. Ecosurveillance also has significant potential impacts on humans; therefore, researchers and policymakers need new conceptual tools to anticipate and mitigate any negative effects. Surveillance studies is an interdisciplinary field in the social sciences, providing a number of insights and practical lessons for predicting and managing the complex impacts (positive and negative, intended and unintended) of surveillance tools and practices. We draw on surveillance studies literature to propose two tools to guide designers and practitioners of ecosurveillance—a ‘red flag checklist’ to anticipate potential problems, and a ‘considerations guide’ to inform design decisions across a wide range of ecosurveillance systems. These tools will help ensure that the coming era of ecosurveillance is guided by responsible and ethical practices towards wildlife and humans alike, while also realizing the potential of these technologies for improving environmental outcomes.publishedVersio

    The Cosmology Large Angular Scale Surveyor (CLASS): 40 GHz Optical Design

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    The Cosmology Large Angular Scale Surveyor (CLASS) instrument will measure the polarization of the cosmic microwave background at 40, 90, and 150 GHz from Cerro Toco in the Atacama desert of northern Chile. In this paper, we describe the optical design of the 40 GHz telescope system. The telescope is a diffraction limited catadioptric design consisting of a front-end Variable-delay Polarization Modulator (VPM), two ambient temperature mirrors, two cryogenic dielectric lenses, thermal blocking filters, and an array of 36 smooth-wall scalar feedhorn antennas. The feed horns guide the signal to antenna-coupled transition-edge sensor (TES) bolometers. Polarization diplexing and bandpass definition are handled on the same microchip as the TES. The feed horn beams are truncated with 10 dB edge taper by a 4 K Lyot-stop to limit detector loading from stray light and control the edge illumination of the front-end VPM. The field-of-view is 19 deg x 14 deg with a resolution for each beam on the sky of 1.5 deg. FWHM

    Development of Space-Flight Compatible Room-Temperature Electronics for the Lynx X-Ray Microcalorimeter

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    We are studying the development of space-flight compatible room-temperature electronics for the Lynx x-ray microcalorimeter (LXM) of the Lynx mission. The baseline readout technique for the LXM is microwave SQUID multiplexing. The key modules at room temperature are the RF electronics module and the digital electronics and event processor (DEEP). The RF module functions as frequency converters and mainly consists of local oscillators and I/Q mixers. The DEEP performs demultiplexing and event processing, and mainly consists of field-programmable gate arrays, ADCs, and DACs. We designed the RF electronics and DEEP to be flight ready, and estimated the power, size, and mass of those modules. There are two boxes each for the RF electronics and DEEP for segmentation, and the sizes of the boxes are 13 in: 13 in: 9 in: for the RF electronics and 15.5 in: 11.5 in: 9.5 in: for the DEEP. The estimated masses are 25.1 kgbox for the RF electronics box and 24.1 kgbox for the DEEP box. The maximum operating power for the RF electronics is 141 W or 70.5 Wbox, and for the DEEP box is 615 W or 308 Wbox. The overall power for those modules is 756 W. We describe the detail of the designs as well as the approaches to the estimation of resources, sizes, masses, and powers

    Physiology as a tool for at-risk animal recovery planning: An analysis of Canadian recovery strategies with global recommendations

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    Many government organizations use recovery planning to synthesize threats, propose management strategies, and determine recovery criteria for threatened wildlife. Little is known about the extent to which physiological knowledge has been used in recovery planning, despite its potential to offer key biological information that could aid in recovery success. Using recovery strategies for at-risk animal species in Canada as a case study, we analyzed the prevalence, purpose, and type of physiological knowledge being used in recovery planning. We found that 73% of strategies contained mention of physiology and that incorporation of physiology has increased since 2006. Of the various types of physiological tools available, reference to stress, immune, thermal, and bioenergetic metrics appeared most frequently. Physiological information was more likely to be found in the background and threat assessment sections compared to action and future research sections, and less likely to be included in strategies for arthropods and birds compared to other taxonomic groups. By synthesizing our results with previous studies, we provide recommendations to encourage the application of physiological tools in recovery planning worldwide, such as increased incorporation of physiology in ongoing threat monitoring, critical habitat assessments, monitoring the success of recovery actions, and modeling responses to future environmental changes.publishedVersio
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