3,929 research outputs found
Understanding Arguments to Protect Farmland in Idaho: Innovative Solutions and Community Insights to Drive Policy Change
Between Spring 2022 and Spring 2023, a team of researchers at Boise State University conducted interviews with people involved in farmland protection efforts. Our goal was to understand how interviewees frame the issue of farmland loss. Frames can draw attention to an issue, contextualize decision-making, and influence the policy solutions considered. Through a frame analysis, we gained a clearer understanding of potential approaches for farmland protection in Idaho.
We conducted 10 semi-structured interviews with individuals representing government agencies, academic institutions, land trusts, non-profit organizations, and farmers. After conducting the interviews, we analyzed the transcripts in a systematic manner to identify recurring message frames pertaining to farmland loss. The analysis process enabled us to map these frames onto potential policy solutions applicable to Idaho.
Our report outlines the advantages and disadvantages of each frame and pinpoints which ones are likely to resonate with specific groups. Our research revealed a diverse range of frames used to address farmland protection, with many interviewees citing multiple frames. The domestic food security, regional economy, and national/global trade frames are expected to have broad appeal, while the national security and environmental benefits frames may appeal to more specific audiences. The threatened resource and cultural importance frames are likely to resonate with those valuing tradition. We identified a variety of solutions, such as agricultural protection areas, support for rural economies, promotion of regenerative agriculture, and expansion of Idaho\u27s Right to Farm Act protections. Our findings underscore the importance of diverse, flexible, and responsive solutions to improve the feasibility of farmland protection in Idaho. We hope that our work will provide a solid basis for future efforts aimed at preserving Idaho\u27s farmland
Chandra Observations of Radio-Loud Quasars at z > 4: X-rays from the Radio Beacons of the Early Universe
We present the results of Chandra observations of six radio-loud quasars
(RLQs) and one optically bright radio-quiet quasar (RQQ) at z = 4.1-4.4. These
observations cover a representative sample of RLQs with moderate radio-loudness
(R ~ 40-400), filling the X-ray observational gap between optically selected
RQQs and the five known blazars at z > 4 (R ~ 800-27000). We study the
relationship between X-ray luminosity and radio-loudness for quasars at high
redshift and constrain RLQ X-ray continuum emission and absorption. From a
joint spectral fit of nine moderate-R RLQs observed by Chandra, we find
tentative evidence for absorption above the Galactic N_H, with a best-fit
neutral intrinsic column density of N_H = 2.4^{+2.0}_{-1.8} x 10^{22} cm^{-2},
consistent with earlier claims of increased absorption toward high-redshift
RLQs. We also search for evidence of an enhanced jet-linked component in the
X-ray emission due to the increased energy density of the cosmic microwave
background (CMB) at high redshift, but we find neither spatial detections of
X-ray jets nor a significant enhancement in the X-ray emission relative to
comparable RLQs at low-to-moderate redshifts. Overall, the z ~ 4-5 RLQs have
basic X-ray properties consistent with comparable RLQs in the local universe,
suggesting that the accretion/jet mechanisms of these objects are similar as
well.Comment: 12 pages, The Astronomical Journal, in pres
The X-Ray Properties of the Optically Brightest Mini-BAL Quasars from the Sloan Digital Sky Survey
We have compiled a sample of 14 of the optically brightest radio-quiet
quasars (~~17.5 and ~~1.9) in the Sloan Digital Sky Survey
Data Release 5 quasar catalog that have C IV mini-BALs present in their
spectra. X-ray data for 12 of the objects were obtained via a Chandra snapshot
survey using ACIS-S, while data for the other two quasars were obtained from
archival XMM-Newton observations. Joint X-ray spectral analysis shows the
mini-BAL quasars have a similar average power-law photon index
() and level of intrinsic absorption () as non-BMB (neither BAL nor mini-BAL) quasars.
Mini-BAL quasars are more similar to non-BMB quasars than to BAL quasars in
their distribution of relative X-ray brightness (assessed with
). Relative colors indicate mild dust reddening in the
optical spectra of mini-BAL quasars. Significant correlations between
and UV absorption properties are confirmed for a sample
of 56 sources combining mini-BAL and BAL quasars with high signal-to-noise
ratio rest-frame UV spectra, which generally supports models in which X-ray
absorption is important in enabling driving of the UV absorption-line wind. We
also propose alternative parametrizations of the UV absorption properties of
mini-BAL and BAL quasars, which may better describe the broad absorption
troughs in some respects.Comment: ApJ accepted; 21 pages, 11 figures, and 9 table
Near Infrared Spectra and Intrinsic Luminosities of Candidate Type II Quasars at 2 < z < 3.4
We present JHK near-infrared (NIR) spectroscopy of 25 candidate Type II
quasars selected from the Sloan Digital Sky Survey, using Triplespec on the
Apache Point Observatory 3.5m telescope, FIRE at the Magellan/Baade 6.5m
telescope, and GNIRS on Gemini. At redshifts of 2 < z < 3.4, our NIR spectra
probe the rest-frame optical region of these targets, which were initially
selected to have strong lines of CIV and Ly alpha, with FWHM<2000 km/s from the
SDSS pipeline. We use the [OIII]5007 line shape as a model for the narrow line
region emission, and find that \halpha\ consistently requires a broad component
with FWHMs ranging from 1000 to 7500 km/s. Interestingly, the CIV lines also
require broad bases, but with considerably narrower widths of 1000 to 4500
km/s. Estimating the extinction using the Balmer decrement and also the
relationship in lower-z quasars between rest equivalent width and luminosity in
the [OIII] line, we find typical A_V values of 0-2 mag, which naturally explain
the attenuated CIV lines relative to Halpha. We propose that our targets are
moderately obscured quasars. We also describe one unusual object with three
distinct velocity peaks in its [OIII] spectrum.Comment: Accepted for publication in ApJ, 18 pages, 14 figure
Evidence for a Two-stage Melting Transition of the Vortex Matter in Bi2Sr2Ca1Cu2O8+d Single Crystals obtained by Muon Spin Rotation
From muon spin rotation measurements on under- to overdoped Bi-2212 crystals
we obtain evidence for a two-stage transition of the vortex matter as a
function of temperature. The first transition is well known and related to the
irreversibility line (IL). The second one is located below the IL and has not
been previously observed. It occurs for all three sets of crystals and is
unrelated to the vortex mobility. Our data are consistent with a two-stage
melting scenario where the intra-planar melting of the vortex lattice and the
inter-planar decoupling of the vortex lines occur independently.Comment: 9 pages and 3 figure
Candidate Type II Quasars at 2 < z < 4.3 in the Sloan Digital Sky Survey III
At low redshifts, dust-obscured quasars often have strong yet narrow
permitted lines in the rest-frame optical and ultraviolet, excited by the
central active nucleus, earning the designation Type II quasars. We present a
sample of 145 candidate Type II quasars at redshifts between 2 and 4.3,
encompassing the epoch at which quasar activity peaked in the universe. These
objects, selected from the quasar sample of the Baryon Oscillation
Spectroscopic Survey of the Sloan Digital Sky Survey III, are characterized by
weak continuum in the rest-frame ultraviolet (typical continuum magnitude of i
\approx 22) and strong lines of CIV and Ly \alpha, with Full Width at Half
Maximum less than 2000 kms-1. The continuum magnitudes correspond to an
absolute magnitude of -23 or brighter at redshift 3, too bright to be due
exclusively to the host galaxies of these objects. Roughly one third of the
objects are detected in the shorter-wavelength bands of the WISE survey; the
spectral energy distributions (SEDs) of these objects appear to be intermediate
between classic Type I and Type II quasars seen at lower redshift. Five objects
are detected at rest frame 6\mu m by Spitzer, implying bolometric luminosities
of several times 10^46 erg s-1. We have obtained polarization measurements for
two objects; they are roughly 3% polarized. We suggest that these objects are
luminous quasars, with modest dust extinction (A_V ~ 0.5 mag), whose
ultraviolet continuum also includes a substantial scattering contribution.
Alternatively, the line of sight to the central engines of these objects may be
partially obscured by optically thick material.Comment: 26 pages, 13 figures, 10 tables, 4 machine readable tables. Accepted
for publication in MNRA
X-ray Sources in the Hubble Deep Field Detected by Chandra
We present first results from an X-ray study of the Hubble Deep Field North
(HDF-N) and its environs obtained using 166 ks of data collected by the
Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-ray
Observatory. This is the deepest X-ray observation ever reported, and in the
HDF-N itself we detect six X-ray sources down to a 0.5--8 keV flux limit of
4E-16 erg cm^-2 s^-1. Comparing these sources with objects seen in
multiwavelength HDF-N studies shows positional coincidences with the extremely
red object NICMOS J123651.74 +621221.4, an active galactic nucleus (AGN), three
elliptical galaxies, and one nearby spiral galaxy. The X-ray emission from the
ellipticals is consistent with that expected from a hot interstellar medium,
and the spiral galaxy emission may arise from a `super-Eddington' X-ray binary
or ultraluminous supernova remnant. Four of the X-ray sources have been
detected at radio wavelengths. We also place X-ray upper limits on AGN
candidates found in the HDF-N, and we present the tightest constraints yet on
X-ray emission from the SCUBA submillimeter source population. None of the 10
high-significance submillimeter sources reported in the HDF-N and its vicinity
is detected with Chandra ACIS. These sources appear to be dominated by star
formation or have AGN with Compton-thick tori and little circumnuclear X-ray
scattering.Comment: 11 pages, ApJ, in press, also available from
http://www.astro.psu.edu/users/niel/hdf/hdf-chandra.htm
The Chandra Deep Field North Survey. IX. Extended X-ray Sources
The ~1 Ms Chandra Deep Field North observation is used to study the extended
X-ray sources in the region surrounding the Hubble Deep Field North (HDF-N),
yielding the most sensitive probe of extended X-ray emission at cosmological
distances to date. A total of six such sources are detected, the majority of
which align with small numbers of optically bright galaxies. Their angular
sizes, band ratios, and X-ray luminosities -- assuming they lie at the same
distances as the galaxies coincident with the X-ray emission -- are generally
consistent with the properties found for nearby groups of galaxies. One source
is notably different and is likely to be a poor-to-moderate X-ray cluster at
high redshift (i.e., z > 0.7). We are also able to place strong constraints on
the optically detected cluster of galaxies ClG 1236+6215 at z=0.85 and the
wide-angle-tail radio galaxy VLA J123725.7+621128 at z~1-2. With rest-frame
0.5--2.0 keV X-ray luminosities of <(3-15)e42 ergs s^{-1}, the environments of
both sources are either likely to have a significant deficit of hot
intra-cluster gas compared to local clusters of galaxies, or they are X-ray
groups. We find the surface density of extended X-ray sources in this
observation to be 167 (+97,-67) deg^{-2} at a limiting soft-band flux of
approximately 3e-16 ergs s^{-1} cm^{-2}. No evolution in the X-ray luminosity
function of clusters is needed to explain this value. (Abridged)Comment: 16 pages, 14 figures (8 color), LaTeX emulateapj5.sty, accepted for
publication by the Astronomical Journal. Manuscript with full resolution
embedded images available at
http://www.astro.psu.edu/users/niel/hdf/hdf-chandra.htm
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