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
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
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
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
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
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 m. 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 m 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
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
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 70,000 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 (MUX)
readout at an initial multiplexing factor of 1000; the cold (100 mK)
readout components are packaged in a MUX 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
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
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
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 He 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 He
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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