154 research outputs found
Predicting Occupancy of Wintering Migratory Birds: Is Microhabitat Information Necessary?
Information regarding microhabitat, here defined as small-scale vegetation structure, is often useful in predicting use of habitat by birds. Quantifying microhabitat, however, is expensive and labor intensive compared to assessment of habitat at a larger scale, possibly from remotely sensed imagery. To assess the importance of microhabitat information in constructing predictive models of habitat occupancy, we compared occupancy models built on the basis of macro- and microhabitat together and separately. We based our models on counts of wintering migratory bird species and vegetation surveys within Tuskegee National Forest, Alabama, completed during winter 2009. Models built from macrohabitat data only outperformed models built from microhabitat data only for five of the six species analyzed. However, the best model for every focal species included both macro- and microhabitat covariates. Pine forestsâexcluding plantationâwere the only land-cover classification important to our focal species, and measures of density of vegetation were important in predicting occupancy. Our results suggest that migrants wintering at our study site select habitat at multiple scalesâspecializing in certain types of cover and then preferring specific structural aspects of vegetation within them. We conclude that microhabitat information is important for inference into use of habitat by wintering migratory birds
An Experimental Investigation into the Effects of Traffic Noise on Distributions of Birds: Avoiding the Phantom Road
Many authors have suggested that the negative effects of roads on animals are largely owing to traffic noise. Although suggestive, most past studies of the effects of road noise on wildlife were conducted in the presence of the other confounding effects of roads, such as visual disturbance, collisions and chemical pollution among others. We present, to our knowledge, the first study to experimentally apply traffic noise to a roadless area at a landscape scaleâthus avoiding the other confounding aspects of roads present in past studies. We replicated the sound of a roadway at intervalsâalternating 4 days of noise on with 4 days offâduring the autumn migratory period using a 0.5 km array of speakers within an established stopover site in southern Idaho. We conducted daily bird surveys along our âPhantom Roadâ and in a nearby control site. We document over a one-quarter decline in bird abundance and almost complete avoidance by some species between noise-on and noise-off periods along the phantom road and no such effects at control sitesâsuggesting that traffic noise is a major driver of effects of roads on populations of animals
An Automated Method for the Detection and Extraction of HI Self-Absorption in High-Resolution 21cm Line Surveys
We describe algorithms that detect 21cm line HI self-absorption (HISA) in
large data sets and extract it for analysis. Our search method identifies HISA
as spatially and spectrally confined dark HI features that appear as negative
residuals after removing larger-scale emission components with a modified CLEAN
algorithm. Adjacent HISA volume-pixels (voxels) are grouped into features in
(l,b,v) space, and the HI brightness of voxels outside the 3-D feature
boundaries is smoothly interpolated to estimate the absorption amplitude and
the unabsorbed HI emission brightness. The reliability and completeness of our
HISA detection scheme have been tested extensively with model data. We detect
most features over a wide range of sizes, linewidths, amplitudes, and
background levels, with poor detection only where the absorption brightness
temperature amplitude is weak, the absorption scale approaches that of the
correlated noise, or the background level is too faint for HISA to be
distinguished reliably from emission gaps. False detection rates are very low
in all parts of the parameter space except at sizes and amplitudes approaching
those of noise fluctuations. Absorption measurement biases introduced by the
method are generally small and appear to arise from cases of incomplete HISA
detection. This paper is the third in a series examining HISA at high angular
resolution. A companion paper (Paper II) uses our HISA search and extraction
method to investigate the cold atomic gas distribution in the Canadian Galactic
Plane Survey.Comment: 39 pages, including 14 figure pages; to appear in June 10 ApJ, volume
626; figure quality significantly reduced for astro-ph; for full resolution,
please see http://www.ras.ucalgary.ca/~gibson/hisa/cgps1_survey
Phenology Effects on Productivity and Hatching-Asynchrony of American Kestrels (\u3cem\u3eFalco sparverius\u3c/em\u3e) Across a Continent
Optimal reproductive performance occurs when birds time reproduction to coincide with peak food availability. Deviation from optimal timing, or mismatch, can affect productivity, though birds may mediate some mismatch effects by altering their incubation behavior. We studied the consequences of nesting timing (i.e., clutch initiation relative to an index of spring start) on productivity across the breeding range of American kestrels (Falco sparverius) in the United States and southern Canada, and associations between nesting timing, incubation behavior, and hatching asynchrony. We used observations from long-term nest box monitoring, remote trail cameras, and community-scientist-based programs to obtain data on clutch initiation, productivity, incubation, and hatching synchrony. Kestrels that initiated clutches after the extended spring index (SI-x, start of spring estimate) had higher rates of nest failure and fewer nestlings than earlier nesters, and effects of nesting timing on productivity were strongest in the Northeast. In contrast, kestrels in the Southwest experienced a more gradual decline in productivity across the season. Spatial effects may be the result of regional differences in growing seasons and temporal nesting windows (duration of nesting season). Specifically, resource availability in the Northeast was highly peaked during the breeding season, potentially resulting in shorter nesting windows. Conversely, resource curves were more prolonged in the Southwest, and growing seasons are becoming longer with climate change, potentially resulting in longer nesting windows. We found an inverse relationship between nesting timing and the onset of male incubation. Males from breeding pairs that initiated clutches after SI-x began incubation sooner than males from breeding pairs that initiated clutches before SI-x. Early-onset of male incubation was positively associated with hatching asynchrony, creating increased age variation in developing young. In sum, nesting phenology relative to the SI-x has consequences for American kestrelsâ productivity, and these consequences vary across space. The early onset of incubation may act as a potential adaptive behavior to advance the average hatch date and spread out energetic demands. Given the effects of nesting timing on productivity, kestrels are likely to be sensitive to climate-driven advances in growing seasons and vulnerable to phenological mismatch, particularly in the Northeast
Expression of human ficolin-2 in hepatocytes confers resistance to infection by diverse hepatotropic viruses
The liver-expressed pattern recognition receptors (PRRs) mannose binding lectin (MBL), ficolin-2 and ficolin-3 contribute to the innate immune response by activating complement. Binding of soluble ficolin-2 to viral pathogens can directly neutralize virus entry. We observed that the human hepatoma cell line HuH7.5, which is routinely used for the study of hepatotropic viruses, is deficient in expression of MBL, ficolin-2 and ficolin-3. We generated a cell line that expressed and secreted ficolin-2. This cell line (HuH7.5 [FCN2]) was more resistant to infection with hepatitis C virus (HCV), ebolavirus (EBOV) and vesicular stomatitis virus (VSV), but surprisingly was more susceptible to infection with rabies virus (RABV). Cell-to-cell spread of HCV was also inhibited in ficolin-2 expressing cells. This illustrates that ficolin-2 expression in hepatocytes contributes to innate resistance to virus infection, but some viruses might utilise ficolin-2 to facilitate entry
Developing GIS-based eastern equine encephalitis vector-host models in Tuskegee, Alabama
<p>Abstract</p> <p>Background</p> <p>A site near Tuskegee, Alabama was examined for vector-host activities of eastern equine encephalomyelitis virus (EEEV). Land cover maps of the study site were created in ArcInfo 9.2<sup>ÂŽ </sup>from QuickBird data encompassing visible and near-infrared (NIR) band information (0.45 to 0.72 Îźm) acquired July 15, 2008. Georeferenced mosquito and bird sampling sites, and their associated land cover attributes from the study site, were overlaid onto the satellite data. SAS 9.1.4<sup>ÂŽ </sup>was used to explore univariate statistics and to generate regression models using the field and remote-sampled mosquito and bird data. Regression models indicated that <it>Culex erracticus </it>and Northern Cardinals were the most abundant mosquito and bird species, respectively. Spatial linear prediction models were then generated in Geostatistical Analyst Extension of ArcGIS 9.2<sup>ÂŽ</sup>. Additionally, a model of the study site was generated, based on a Digital Elevation Model (DEM), using ArcScene extension of ArcGIS 9.2<sup>ÂŽ</sup>.</p> <p>Results</p> <p>For total mosquito count data, a first-order trend ordinary kriging process was fitted to the semivariogram at a partial sill of 5.041 km, nugget of 6.325 km, lag size of 7.076 km, and range of 31.43 km, using 12 lags. For total adult <it>Cx. erracticus </it>count, a first-order trend ordinary kriging process was fitted to the semivariogram at a partial sill of 5.764 km, nugget of 6.114 km, lag size of 7.472 km, and range of 32.62 km, using 12 lags. For the total bird count data, a first-order trend ordinary kriging process was fitted to the semivariogram at a partial sill of 4.998 km, nugget of 5.413 km, lag size of 7.549 km and range of 35.27 km, using 12 lags. For the Northern Cardinal count data, a first-order trend ordinary kriging process was fitted to the semivariogram at a partial sill of 6.387 km, nugget of 5.935 km, lag size of 8.549 km and a range of 41.38 km, using 12 lags. Results of the DEM analyses indicated a statistically significant inverse linear relationship between total sampled mosquito data and elevation (R<sup>2 </sup>= -.4262; p < .0001), with a standard deviation (SD) of 10.46, and total sampled bird data and elevation (R<sup>2 </sup>= -.5111; p < .0001), with a SD of 22.97. DEM statistics also indicated a significant inverse linear relationship between total sampled <it>Cx. erracticus </it>data and elevation (R<sup>2 </sup>= -.4711; p < .0001), with a SD of 11.16, and the total sampled Northern Cardinal data and elevation (R<sup>2 </sup>= -.5831; p < .0001), SD of 11.42.</p> <p>Conclusion</p> <p>These data demonstrate that GIS/remote sensing models and spatial statistics can capture space-varying functional relationships between field-sampled mosquito and bird parameters for determining risk for EEEV transmission.</p
The interstellar medium towards the Ara OB1 region
We present high resolution (R ~ 4 km/s) absorption measurements of the
interstellar NaI and CaII lines measured towards 14 early-type stars of
distance 123 pc - 1650 pc, located in the direction of the Ara OB1 stellar
cluster. The line profiles can broadly be split into four distinct groupings of
absorption component velocity, and we have attempted to identify an origin and
distance to each of these interstellar features. For gas with absorption
covering the velocity range -10 km/s < V_helio < +10 km/s, we can identify the
absorbing medium with local gas belonging to the Lupus-Norma interstellar
cavity located between 100 and 485 pc in this galactic direction. Gas with
velocities spanning the range -20 km/s < V_helio < +20 km/s is detected towards
stars with distances of 570-800 pc. We identify a wide-spread interstellar
feature at V_helio ~ -15 km/s with the expanding HI shell called GSH 337+00-05,
which is now placed at a distance of ~530 pc.Comment: 12 pages, 5 figures, accepted for publication in Astrophysics & Space
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Developing Models for the Forage Ratios of Culiseta melanura and Culex erraticus using Species Characteristics for Avian Hosts
Studies of mosquito preferences for avian hosts have found that some bird species are at greater risk than others of being fed upon by mosquitoes. The ecological factors that determine this interspecific variation in avian host use by mosquitoes have been little studied, despite the possibility that such variation may influence spatial and temporal patterns of the occurrence of mosquito-borne pathogens. Our objective was to identify ecological variables associated with the avian host forage ratios estimated from a previous study of mosquito feeding patterns in Tuskegee National Forest, AL. We used species' characteristics derived from the literature to develop multiple linear regression models for the forage ratios of Culiseta melanura (Coquillett) and Culex erraticus (Dyar & Knab) for avian hosts. We found that habitat-edge association and body mass of avian host species were the best predictors of forage ratios of Cx. erraticus for avian hosts. Although no avian host traits were inferred to be strong predictors of forage ratios of Cs. melanura, body mass had the greatest importance weight among those considered. Our results suggest that characteristics of avian hosts may predict their levels of use by some mosquito species.This is the publisherâs final pdf. The published article is copyrighted by Entomological Society of America and can be found at: http://www.entsoc.org/.Keywords: avian host, Culex erraticus, Culiseta melanura, forage ratioKeywords: avian host, Culex erraticus, Culiseta melanura, forage rati
Achieving a quantum smart workforce
Interest in building dedicated Quantum Information Science and Engineering
(QISE) education programs has greatly expanded in recent years. These programs
are inherently convergent, complex, often resource intensive and likely require
collaboration with a broad variety of stakeholders. In order to address this
combination of challenges, we have captured ideas from many members in the
community. This manuscript not only addresses policy makers and funding
agencies (both public and private and from the regional to the international
level) but also contains needs identified by industry leaders and discusses the
difficulties inherent in creating an inclusive QISE curriculum. We report on
the status of eighteen post-secondary education programs in QISE and provide
guidance for building new programs. Lastly, we encourage the development of a
comprehensive strategic plan for quantum education and workforce development as
a means to make the most of the ongoing substantial investments being made in
QISE.Comment: 18 pages, 2 figures, 1 tabl
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