78 research outputs found

    Using integrated resource management and the public trust doctrine to examine wildlife management practices in northern Labrador: a case study on the George River caribou hunting ban

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    The people of Labrador, especially the Inuit, rely on their surrounding resources to sustain themselves and their culture. In particular, the Labrador Inuit depended upon the George River Caribou Herd (GRCH), once one of the largest caribou herds in the world, to provide them with a staple food supply, nourishment, materials, and facilitate the intergenerational sharing of knowledge and important social and cultural norms, all of which are critical to life in Arctic and subarctic environments. This woodland caribou population, however, has declined by 99% over much of it range resulting in a hunting ban, and consequently, a cascade of impacts on the Inuit of northern Labrador. Examining and understanding these impacts is the focus of this thesis. As management of wildlife in North America is to follow the Public Trust Doctrine—to manage wildlife in the public trust—this thesis helps bring the information of Inuit impacts into the discussion to help inform future best practices for more accountable, responsible, and locally responsive wildlife management efforts in the North

    Measuring and Correcting Wind-Induced Pointing Errors of the Green Bank Telescope Using an Optical Quadrant Detector

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    Wind-induced pointing errors are a serious concern for large-aperture high-frequency radio telescopes. In this paper, we describe the implementation of an optical quadrant detector instrument that can detect and provide a correction signal for wind-induced pointing errors on the 100m diameter Green Bank Telescope (GBT). The instrument was calibrated using a combination of astronomical measurements and metrology. We find that the main wind-induced pointing errors on time scales of minutes are caused by the feedarm being blown along the direction of the wind vector. We also find that wind-induced structural excitation is virtually non-existent. We have implemented offline software to apply pointing corrections to the data from imaging instruments such as the MUSTANG 3.3 mm bolometer array, which can recover ~70% of sensitivity lost due to wind-induced pointing errors. We have also performed preliminary tests that show great promise for correcting these pointing errors in real-time using the telescope's subreflector servo system in combination with the quadrant detector signal.Comment: 17 pages, 11 figures; accepted for publication in PAS

    The ABCD of obesity: An EASO position statement on a diagnostic term with clinical and scientific implications

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    Obesity is a frequent, serious, complex, relapsing, and chronic disease process that represents a major public health problem. The coining of obesity as an adiposity-based chronic disease (ABCD) is of particular relevance being in line with EASO’s proposal to improve the International Classification of Diseases ICD-11 diagnostic criteria for obesity based on three dimensions, namely etiology, degree of adiposity, and health risks. The body mass index as a unique measurement of obesity does not reflect the whole complexity of the disease. Obesity complications are mainly determined by 2 pathological processes, i.e., physical forces (fat mass disease) as well as endocrine and immune responses (sick fat disease), which are embedded in a cultural and physical context leading to a specific ABCD stage

    An open source, FPGA-based LeKID readout for BLAST-TNG: Pre-flight results

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    We present a highly frequency multiplexed readout for large-format superconducting detector arrays intended for use in the next generation of balloon-borne and space-based sub-millimeter and far-infrared missions. We will demonstrate this technology on the upcoming NASA Next Generation Balloon-borne Large Aperture Sub-millimeter Telescope (BLAST-TNG) to measure the polarized emission of Galactic dust at wavelengths of 250, 350 and 500 microns. The BLAST-TNG receiver incorporates the first arrays of Lumped Element Kinetic Inductance Detectors (LeKID) along with the first microwave multiplexing readout electronics to fly in a space-like environment and will significantly advance the TRL for these technologies. After the flight of BLAST-TNG, we will continue to improve the performance of the detectors and readout electronics for the next generation of balloon-borne instruments and for use in a future FIR Surveyor. Read More: http://www.worldscientific.com/doi/abs/10.1142/S225117171641003

    Instrumental performance and results from testing of the BLAST-TNG receiver, submillimeter optics, and MKID arrays

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    Polarized thermal emission from interstellar dust grains can be used to map magnetic fields in star forming molecular clouds and the diffuse interstellar medium (ISM). The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) flew from Antarctica in 2010 and 2012 and produced degree-scale polarization maps of several nearby molecular clouds with arcminute resolution. The success of BLASTPol has motivated a next-generation instrument, BLAST-TNG, which will use more than 3000 linear polarization sensitive microwave kinetic inductance detectors (MKIDs) combined with a 2.5m diameter carbon fiber primary mirror to make diffraction-limited observations at 250, 350, and 500 μ\mum. With 16 times the mapping speed of BLASTPol, sub-arcminute resolution, and a longer flight time, BLAST-TNG will be able to examine nearby molecular clouds and the diffuse galactic dust polarization spectrum in unprecedented detail. The 250 μ\mum detector array has been integrated into the new cryogenic receiver, and is undergoing testing to establish the optical and polarization characteristics of the instrument. BLAST-TNG will demonstrate the effectiveness of kilo-pixel MKID arrays for applications in submillimeter astronomy. BLAST-TNG is scheduled to fly from Antarctica in December 2017 for 28 days and will be the first balloon-borne telescope to offer a quarter of the flight for "shared risk" observing by the community.Comment: Presented at SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII, June 29th, 201

    The optical design of the six-meter CCAT-prime and Simons Observatory telescopes

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    A common optical design for a coma-corrected, 6-meter aperture, crossed-Dragone telescope has been adopted for the CCAT-prime telescope of CCAT Observatory, Inc., and for the Large Aperture Telescope of the Simons Observatory. Both are to be built in the high altitude Atacama Desert in Chile for submillimeter and millimeter wavelength observations, respectively. The design delivers a high throughput, relatively flat focal plane, with a field of view 7.8 degrees in diameter for 3 mm wavelengths, and the ability to illuminate >100k diffraction-limited beams for < 1 mm wavelengths. The optics consist of offset reflecting primary and secondary surfaces arranged in such a way as to satisfy the Mizuguchi-Dragone criterion, suppressing first-order astigmatism and maintaining high polarization purity. The surface shapes are perturbed from their standard conic forms in order to correct coma aberrations. We discuss the optical design, performance, and tolerancing sensitivity. More information about CCAT-prime can be found at ccatobservatory.org and about Simons Observatory at simonsobservatory.org.Comment: Event: SPIE Astronomical Telescopes + Instrumentation, 2018, Austin, Texas, USA; Proceedings Volume 10700, Ground-based and Airborne Telescopes VII; 1070041 (2018

    The Simons Observatory: Magnetic Sensitivity Measurements of Microwave SQUID Multiplexers

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    The Simons Observatory (SO) will be a cosmic microwave background (CMB) survey experiment with three small-aperture telescopes and one large-aperture telescope, which will observe from the Atacama Desert in Chile. In total, SO will field ∼\sim70,000 transition-edge sensor (TES) bolometers in six spectral bands centered between 27 and 280 GHz in order to achieve the sensitivity necessary to measure or constrain numerous cosmological quantities. The SO Universal Focal Plane Modules (UFMs) each contain a 150 mm diameter TES detector array, horn or lenslet optical coupling, cold readout components, and magnetic shielding. SO will use a microwave SQUID multiplexing (μ\muMUX) readout at an initial multiplexing factor of ∼\sim1000; the cold (100 mK) readout components are packaged in a μ\muMUX readout module, which is part of the UFM, and can also be characterized independently. The 100 mK stage TES bolometer arrays and microwave SQUIDs are sensitive to magnetic fields, and their measured response will vary with the degree to which they are magnetically shielded. We present measurements of the magnetic pickup of test microwave SQUID multiplexers as a study of various shielding configurations for the Simons Observatory. We discuss how these measurements motivated the material choice and design of the UFM magnetic shielding.Comment: 5 pages, 6 figures, conference proceedings submitted to IEEE Transactions on Applied Superconductivit

    Holographic Measurement and Improvement of the Green Bank Telescope Surface

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    We describe the successful design, implementation, and operation of a 12 GHz holography system installed on the Robert C. Byrd Green Bank Telescope (GBT). We have used a geostationary satellite beacon to construct high-resolution holographic images of the telescope mirror surface irregularities. These images have allowed us to infer and apply improved position offsets for the 2209 actuators which control the active surface of the primary mirror, thereby achieving a dramatic reduction in the total surface error (from 390 microns to ~240 microns, rms). We have also performed manual adjustments of the corner offsets for a few panels. The expected improvement in the radiometric aperture efficiency has been rigorously modeled and confirmed at 43 GHz and 90 GHz. The improvement in the telescope beam pattern has also been measured at 11.7 GHz with greater than 60 dB of dynamic range. Symmetric features in the beam pattern have emerged which are consistent with a repetitive pattern in the aperture due to systematic panel distortions. By computing average images for each tier of panels from the holography images, we confirm that the magnitude and direction of the panel distortions, in response to the combination of gravity and thermal gradients, are in general agreement with finite-element model predictions. The holography system is now fully integrated into the GBT control system, and by enabling the telescope staff to monitor the health of the individual actuators, it continues to be an essential tool to support high-frequency observations.Comment: Accepted for publication in PASP. Contains 28 pages with 2 tables and 9 figures (several at reduced quality). The full resolution version is available at http://wwwlocal.gb.nrao.edu/ptcs/papers/Hunter2011/gbtholo.ps.gz (34MB gzip file unpacks to 134MB postscript

    European association for the study of obesity position statement on the global COVID-19 pandemic

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    COVID-19, the infectious disease caused by the coronavirus SARS-CoV-2, was declared a pandemic by the World Health Organization on March 12, 2020. The European Association for the Study of Obesity (EASO), as a scientific and medical society dedicated to the promotion of health and well-being, is greatly concerned about this global health challenge and its significant impacts on individuals, families, communities, health systems, nations, and wider society

    The Balloon-Borne Large Aperture Submillimeter Telescope Observatory

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    The BLAST Observatory is a proposed superpressure balloon-borne polarimeter designed for a future ultra-long duration balloon campaign from Wanaka, New Zealand. To maximize scientific output while staying within the stringent superpressure weight envelope, BLAST will feature new 1.8m off-axis optical system contained within a lightweight monocoque structure gondola. The payload will incorporate a 300L 4^4He cryogenic receiver which will cool 8,274 microwave kinetic inductance detectors (MKIDs) to 100mK through the use of an adiabatic demagnetization refrigerator (ADR) in combination with a 3^3He sorption refrigerator all backed by a liquid helium pumped pot operating at 2K. The detector readout utilizes a new Xilinx RFSOC-based system which will run the next-generation of the BLAST-TNG KIDPy software. With this instrument we aim to answer outstanding questions about dust dynamics as well as provide community access to the polarized submillimeter sky made possible by high-altitude observing unrestricted by atmospheric transmission. The BLAST Observatory is designed for a minimum 31-day flight of which 70%\% will be dedicated to observations for BLAST scientific goals and the remaining 30%\% will be open to proposals from the wider astronomical community through a shared-risk proposals program.Comment: Presented at SPIE Ground-based and Airborne Telescopes VIII, December 13-18, 202
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