1,341 research outputs found
Nest-Site Selection and Nest Survival of the Rusty Blackbird: Does Timber Management Adjacent to Wetlands Create Ecological Traps?
Animals are subject to ecological traps when anthropogenic changes create habitat that appears suitable but when selected results in decreased fitness. The Rusty Blackbird (Euphagus carolinus) breeds in boreal wetlands and has declined by 85ā95% over the last half century. We studied nest-site selection and daily nest survival rate (DSR) of 43 Rusty Blackbird nests in northern New England and evaluated whether regenerating logged areas adjacent to wetlands created ecological traps. Although nesting adults avoided high-canopied forests and selected areas with dense balsam fir (Abies balasmea) 1 to 3 m high, those characteristics were not associated with DSR. Conversely, the frequency of speckled alder (Alnus incana) and sedges (Cyperaceae) in the nest plot varied with DSR, suggesting that the risk of predation of nests within wetlands was lower. DSR also varied with past logging; nests in plots not harvested recently were 2.3x more likely to fledge young than nests in plots harvested within 20 years. When logging extends to the edges of or into wetlands, the subsequent dense regenerating conifers appear to attract Rusty Blackbirds to nest closer to or within these human-altered uplands, exposing their nests to increased predation not typical of unaltered wetlands. Three surrogates for habitat preference did not differ by timber-management history, suggesting that the birds do not prefer habitats that increase their fitness. Rusty Blackbirds nesting in harvested wetlands may be subject to āequal preferenceā ecological traps, and we suggest that buffers 75 m wide around the perimeter of suitable wetlands should increase DSR
Transformed Minds
In this brief collection of essays, professors who teach in the Department of History and Government at Cedarville University explore the biblical foundation for the academic disciplines unique to their Department. The Excerpt (above) contains the full text of the book.https://digitalcommons.cedarville.edu/faculty_books/1182/thumbnail.jp
Late Glacial to Holocene relative sea-level change in Assynt, northwest Scotland, UK
Relative sea-level change (RSL), from the Late Glacial through to the late Holocene, is reconstructed for the Assynt region, northwest Scotland, based on bio- and lithostratigraphical analysis. Four new radiocarbon-dated sea-level index points help constrain RSL change for the Late Glacial to the late Holocene. These new data, in addition to published material, capture the RSL fall during the Late Glacial and the rise and fall associated with the mid-Holocene highstand. Two of these index points constrain the Late Glacial RSL history in Assynt for the first time, reconstructing RSL falling from 2.47 Ā± 0.59 m OD to 0.15 Ā± 0.59 m OD at c. 14,000ā15,000 cal yr BP. These new data test model predictions of glacial isostatic adjustment (GIA), particularly during the early deglacial period which is currently poorly constrained throughout the British Isles. Whilst the empirical data from the mid- to late-Holocene to present matches quite well with the recent GIA model output, there is a relatively poor fit between the timing of the Late Glacial RSL fall and early Holocene RSL rise. This mismatch, also evident elsewhere in northwest Scotland, may result from uncertainties associated with both the global and local ice components of GIA models.</jats:p
Activation of gene expression by detergent-like protein domains
The mechanisms by which transcriptional activation domains (tADs) initiate eukaryotic gene expression have been an enigma for decades because most tADs lack specificity in sequence, structure, and interactions with targets. Machine learning analysis of data sets of tAD sequences generated in vivo elucidated several functionality rules: the functional tAD sequences should (i) be devoid of or depleted with basic amino acid residues, (ii) be enriched with aromatic and acidic residues, (iii) be with aromatic residues localized mostly near the terminus of the sequence, and acidic residues localized more internally within a span of 20ā30 amino acids, (iv) be with both aromatic and acidic residues preferably spread out in the sequence and not clustered, and (v) not be separated by occasional basic residues. These and other more subtle rules are not absolute, reflecting absence of a tAD consensus sequence, enormous variability, and consistent with surfactant-like tAD biochemical properties. The findings are compatible with the paradigm-shifting nucleosome detergent mechanism of gene expression activation, contributing to the development of the liquid-liquid phase separation model and the biochemistry of near-stochastic functional allosteric interactions
Following the TraCS of exoplanets with Pan-Planets: Wendelstein-1b and Wendelstein-2b
Hot Jupiters seem to get rarer with decreasing stellar mass. The goal of the
Pan-Planets transit survey was the detection of such planets and a statistical
characterization of their frequency. Here, we announce the discovery and
validation of two planets found in that survey, Wendelstein-1b and
Wendelstein-2b, which are two short-period hot Jupiters that orbit late K host
stars. We validated them both by the traditional method of radial velocity
measurements with the HIgh Resolution Echelle Spectrometer (HIRES) and the
Habitable-zone Planet Finder (HPF) instruments and then by their Transit Color
Signature (TraCS). We observed the targets in the wavelength range of Angstr\"om and performed a simultaneous multiband transit fit and
additionally determined their thermal emission via secondary eclipse
observations. Wendelstein-1b is a hot Jupiter with a radius of
and mass of ,
orbiting a K7V dwarf star at a period of d, and has an estimated surface
temperature of about K. Wendelstein-2b is a hot Jupiter with
a radius of and a mass of
, orbiting a K6V dwarf star at a period of
d, and has an estimated surface temperature of about
K. With this, we demonstrate that multiband photometry is
an effective way of validating transiting exoplanets, in particular for fainter
targets since radial velocity (RV) follow-up becomes more and more costly for
those targets.Comment: 14 pages, 12 figures. Accepted for publication in A&
Kepler-503b: An Object at the Hydrogen Burning Mass Limit Orbiting a Subgiant Star
Using spectroscopic radial velocities with the APOGEE instrument and Gaia
distance estimates, we demonstrate that Kepler-503b, currently considered a
validated Kepler planet, is in fact a brown-dwarf/low-mass star in a nearly
circular 7.2-day orbit around a subgiant star. Using a mass estimate for the
primary star derived from stellar models, we derive a companion mass and radius
of () and
(),
respectively. Assuming the system is coeval, the evolutionary state of the
primary indicates the age is Gyr. Kepler-503b sits right at the
hydrogen burning mass limit, straddling the boundary between brown dwarfs and
very low-mass stars. More precise radial velocities and secondary eclipse
spectroscopy with James Webb Space Telescope will provide improved measurements
of the physical parameters and age of this important system to better constrain
and understand the physics of these objects and their spectra. This system
emphasizes the value of radial velocity observations to distinguish a genuine
planet from astrophysical false positives, and is the first result from the
SDSS-IV monitoring of Kepler planet candidates with the multi-object APOGEE
instrument.Comment: Accepted for publication in ApJL, 12 pages, 3 figures, 2 table
The potential of trading activity income to fund third sector organisations operating in deprived areas
In the United Kingdom, as in other countries, Third Sector Organisations (TSOs) have been drawn towards income sources associated with trading activities (Teasdale, 2010), but many remain reliant on grant funding to support such activities (Chell, 2007). Using a multivariate analysis approach and data from the National Survey of Charities and Social Enterprises (NSCSE), it is found that trading activities are used relatively commonly in deprived areas. These organisations are also more likely to attempt to access public sector funds. This suggests policy-makers need to consider the impact of funding cuts on TSOs in the most deprived areas as TSOs are unlikely achieve their objectives without continuing support
Funerary Artifacts, Social Status, and Atherosclerosis in Ancient Peruvian Mummy Bundles
Background: Evidence of atherosclerotic plaques in ancient populations has led to the reconsideration of risk factors for heart disease and of the common belief that it is a disease of modern times.
Methods: Fifty-one wrapped mummy bundles excavated from the sites of Huallamarca, Pedreros, and Rinconada La Molina from the Puruchuco Museum collection in Lima, Peru, were scanned using computed tomography to investigate the presence of atherosclerosis. Funerary artifacts contained within the undisturbed mummy bundles were analyzed as an attempt to infer the social status of the individuals to correlate social status with evidence of heart disease in this ancient Peruvian group. This work also provides an inventory of the museum mummy collection to guide and facilitate future research.
Results: Statistical analysis concluded that there is little association between the types of grave goods contained within the bundles when the groups are pooled together. However, some patterns of artifact type, material, atherosclerosis, and sex emerge when the 3 excavation sites are analyzed separately.
Conclusions: From the current sample, it would seem that social class is difficult to discern, but those from Huallamarca have the most markers of elite status. We had hypothesized that higher-status individuals may have had lifestyles that would place them at a higher risk for atherogenesis. There seems to be some indication of this within the site of Huallamarca, but it is inconclusive in the other 2 archeological sites. It is possible that a larger sample size in the future could reveal more statistically significant results
Genomic Correlates of Atherosclerosis in Ancient Humans
Paleogenetics offers a unique opportunity to study human evolution, population dynamics, and disease evolution in situ. Although histologic and computed x-ray tomographic investigations of ancient mummies have clearly shown that atherosclerosis has been present in humans for more than 5,000 years, limited data are available on the presence of genetic predisposition for cardiovascular disease in ancient human populations. In a previous whole-genome study of the Tyrolean Iceman, a 5,300-year-old glacier mummy from the Alps, an increased risk for coronary heart disease was detected. The Icemanās genome revealed several single nucleotide polymorphisms that are linked with cardiovascular disease in genome-wide association studies. Future genetic studies of ancient humans from various geographic origins and time periods have the potential to provide more insights into the presence and possible changes of genetic risk factors in our ancestors. The study of ancient humans and a better understanding of the interaction between environmental and genetic influences on the development of heart diseases may lead to a more effective prevention and treatment of the most common cause of death in the modern world
Genomic analysis of estrogen cascade reveals histone variant H2A.Z associated with breast cancer progression
We demonstrate an integrated approach to the study of a transcriptional regulatory cascade involved in the progression of breast cancer and we identify a protein associated with disease progression. Using chromatin immunoprecipitation and genome tiling arrays, whole genome mapping of transcription factor-binding sites was combined with gene expression profiling to identify genes involved in the proliferative response to estrogen (E2). Using RNA interference, selected ERĪ± and c-MYC gene targets were knocked down to identify mediators of E2-stimulated cell proliferation. Tissue microarray screening revealed that high expression of an epigenetic factor, the E2-inducible histone variant H2A.Z, is significantly associated with lymph node metastasis and decreased breast cancer survival. Detection of H2A.Z levels independently increased the prognostic power of biomarkers currently in clinical use. This integrated approach has accelerated the identification of a molecule linked to breast cancer progression, has implications for diagnostic and therapeutic interventions, and can be applied to a wide range of cancers
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