196 research outputs found
Removal of Invasive Plants from Pando Exclosure 2018
On July 10-11, 2018 volunteers and staff from Great Old Broads for Wilderness and Grand Canyon Trust removed invasive plants from the Pando exclosure, a fenced portion of the Pando Clone aspen forest adjacent to Fish Lake, in Central Utah. This area has been fenced to restore a portion of the Pando Clone that has been lacking recruitment for decades, by protecting young aspen from browsing by deer and cattle. We have been removing invasive species for five years from this exclosure.
The 2018 trip included 10 women and one staffer of Great Old Broads for Wilderness, from the states of Utah, Colorado and Oregon (Fig. 1). There were also four staff from Grand Canyon Trust (Marc Coles-Ritchie, Mary O\u27Brien, Lisa Winters and Lisa Clark). One of the volunteers and Mary O\u27Brien are both Board members of Great Old Broads for Wilderness. Marc Coles-Ritchie communicated with Kurt Robins, District Ranger for the Fremont Ranger District, before the trip to explain the weeding plan
Pando Clone Recovery: Repeat Photos 2014-2019
The world\u27s largest known clone of aspen (Populus tremuloides), called the Pando Clone is located in the Fishlake National Forest in central Utah. For many decades, significant pressure from ungulate (deer and cattle) browsing has prevented growth of young aspen stems in to trees that would replace the mature trees as they die of natural causes. There has been concern that this impressive 104-acre Pando Clone could be lost altogether due to the excessive browsing of young aspen stems. In 2013, 16 acres of this clone were fenced to exclude all ungulates (deer and cattle) so that recovery of aspen could occur in a portion of the clone
Non-Gaussianity from Self-Ordering Scalar Fields
The Universe may harbor relics of the post-inflationary epoch in the form of
a network of self-ordered scalar fields. Such fossils, while consistent with
current cosmological data at trace levels, may leave too weak an imprint on the
cosmic microwave background and the large-scale distribution of matter to allow
for direct detection. The non-Gaussian statistics of the density perturbations
induced by these fields, however, permit a direct means to probe for these
relics. Here we calculate the bispectrum that arises in models of self-ordered
scalar fields. We find a compact analytic expression for the bispectrum,
evaluate it numerically, and provide a simple approximation that may be useful
for data analysis. The bispectrum is largest for triangles that are aligned
(have edges ) as opposed to the local-model
bispectrum, which peaks for squeezed triangles (), and
the equilateral bispectrum, which peaks at . We
estimate that this non-Gaussianity should be detectable by the Planck satellite
if the contribution from self-ordering scalar fields to primordial
perturbations is near the current upper limit.Comment: 11 pages, 1 figur
Halo Clustering with Non-Local Non-Gaussianity
We show how the peak-background split can be generalized to predict the
effect of non-local primordial non-Gaussianity on the clustering of halos. Our
approach is applicable to arbitrary primordial bispectra. We show that the
scale-dependence of halo clustering predicted in the peak-background split
(PBS) agrees with that of the local-biasing model on large scales. On smaller
scales, k >~ 0.01 h/Mpc, the predictions diverge, a consequence of the
assumption of separation of scales in the peak-background split. Even on large
scales, PBS and local biasing do not generally agree on the amplitude of the
effect outside of the high-peak limit. The scale dependence of the biasing -
the effect that provides strong constraints to the local-model bispectrum - is
far weaker for the equilateral and self-ordering-scalar-field models of
non-Gaussianity. The bias scale dependence for the orthogonal and folded models
is weaker than in the local model (~ 1/k), but likely still strong enough to be
constraining. We show that departures from scale-invariance of the primordial
power spectrum may lead to order-unity corrections, relative to predictions
made assuming scale-invariance - to the non-Gaussian bias in some of these
non-local models for non-Gaussianity. An Appendix shows that a non-local model
can produce the local-model bispectrum, a mathematical curiosity we uncovered
in the course of this investigation.Comment: 12 pages, 4 figures; submitted to Phys. Rev. D; v2: references added;
v3: some more comments on kernel-bispectrum relation in appendi
Recovery of ammonia from wastewater through chemical precipitation
Chemical precipitation is a consolidated technique applied in wastewater treatment to remove and recover phosphorous and ammonium that remain in the effluent after the anaerobic digestion treatment. The precipitate is magnesium ammonium phosphate hexahydrate (MgNH4PO4·6H2O), also known as struvite, and it is sold as a slow-release fertiliser. However, the value of struvite is quite low and has a limited market. Furthermore, it precipitates with heavy metals and other impurities that need to be removed to make the fertiliser commercially viable. This study looked at the thermal decomposition of struvite to recover added value products and recycle the magnesium for further precipitation. A kinetic study was carried out to understand the mechanism of decomposition and the formation of the different solid phases, which is fundamental for the design and optimisation of the technology. The thermogravimetric study confirmed that thermal decomposition is possible, but ammonia could not be completely released below 250 °C. The thermal analysis also led to the determination of the energy required for the decomposition, found to be 1.87 kJ g−1, which also includes the evaporation of water and ammonia. The kinetic study through the isoconversional method showed the presence of two major reactions, and the model-fitting approach identified the diffusion model as the best fit for the first reaction. The activation energy of the first reaction found with this method was 0.24 kJ g−1, comparable with the data obtained from the isoconversional method. The two-stage decomposition reactions were proposed, and the final calcination product was confirmed as magnesium pyrophosphate, which could be used in agriculture or dissolved in diluted mineral acids solution to separate the phosphate from the magnesium
Introspective Symmetries
The practical unification of context-free grammar and von Neumann machines has enabled telephony, and current trends suggest that the investigation of write-ahead logging will soon emerge. Here, we confirm the understanding of context-free grammar, which embodies the essential principles of software engineering [13]. In order to surmount this obstacle, we use distributed methodologies to demonstrate that IPv4 can be made permutable, ambimorphic, and random
T Cell Migration from Inflamed Skin to Draining Lymph Nodes Requires Intralymphatic Crawling Supported by ICAM-1/LFA-1 Interactions.
T cells are the most abundant cell type found in afferent lymph, but their migration through lymphatic vessels (LVs) remains poorly understood. Performing intravital microscopy in the murine skin, we imaged T cell migration through afferent LVs in vivo. T cells entered into and actively migrated within lymphatic capillaries but were passively transported in contractile collecting vessels. Intralymphatic T cell number and motility were increased during contact-hypersensitivity-induced inflammation and dependent on ICAM-1/LFA-1 interactions. In vitro, blockade of endothelial cell-expressed ICAM-1 reduced T cell adhesion, crawling, and transmigration across lymphatic endothelium and decreased T cell advancement from capillaries into lymphatic collectors in skin explants. In vivo, T cell migration to draining lymph nodes was significantly reduced upon ICAM-1 or LFA-1 blockade. Our findings indicate that T cell migration through LVs occurs in distinct steps and reveal a key role for ICAM-1/LFA-1 interactions in this process
General non-rotating perfect-fluid solution with an abelian spacelike C_3 including only one isometry
The general solution for non-rotating perfect-fluid spacetimes admitting one
Killing vector and two conformal (non-isometric) Killing vectors spanning an
abelian three-dimensional conformal algebra (C_3) acting on spacelike
hypersurfaces is presented. It is of Petrov type D; some properties of the
family such as matter contents are given. This family turns out to be an
extension of a solution recently given in \cite{SeS} using completely different
methods. The family contains Friedman-Lema\^{\i}tre-Robertson-Walker particular
cases and could be useful as a test for the different FLRW perturbation
schemes. There are two very interesting limiting cases, one with a non-abelian
G_2 and another with an abelian G_2 acting non-orthogonally transitively on
spacelike surfaces and with the fluid velocity non-orthogonal to the group
orbits. No examples are known to the authors in these classes.Comment: Submitted to GRG, Latex fil
Uncertainty in 2-point correlation function estimators and BAO detection in SDSS DR7
We study the uncertainty in different two-point correlation function (2PCF)
estimators in currently available galaxy surveys. This is motivated by the
active subject of using the baryon acoustic oscillations (BAOs) feature in the
correlation function as a tool to constrain cosmological parameters, which
requires a fine analysis of the statistical significance. We discuss how
estimators are affected by both the uncertainty in the mean density
and the integral constraint
which necessarily causes a bias. We quantify both effects for currently
available galaxy samples using simulated mock catalogues of the Sloan Digital
Sky Survey (SDSS) following a lognormal model, with a Lambda-Cold Dark Matter
() correlation function and similar properties as the
samples (number density, mean redshift for the correlation
function, survey geometry, mass-luminosity bias). Because we need extensive
simulations to quantify small statistical effects, we cannot use realistic
N-body simulations and some physical effects are neglected. Our simulations
still enable a comparison of the different estimators by looking at their
biases and variances. We also test the reliability of the BAO detection in the
SDSS samples and study the compatibility of the data results with our
simulations.Comment: 14 pages, 6 figures, 3 table
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Multi-criteria discovery, design and manufacturing to realise nanomaterial potential
Advanced nanomaterials have a central role to play in the pursuit of sustainable development goals. Applications span sectors, including energy, medicine and environmental clean-up. However, despite an explosion in their discovery and synthesis, these materials are struggling to make it through to commercial production. Their development is hampered by costly, resource intensive and scale-sensitive processes. Herein, we highlight widespread early-stage reliance on single metric optimisation as a primary cause of development failure and, conversely, emphasise the importance of multi-criteria thinking within both research design and execution, and particularly through discovery and design stages. We formulate the PSEC challenge (i.e. Performance, Scalability, Environment and Cost) as a means to integrate broader sustainability thinking with precise technical solutions. We propose overt emphasis on a correspondingly expanded specification of critical material attributes to better direct and integrate research. We highlight the potential for the development of MCDA (multi-criteria decision aiding) tools and opportunities for generating, consolidating, and extensively exploiting good quality whole-system data. Our paper represents a community call-to-action so that nanomaterial discoveries can reach the markets and fulfil their sustainable development potential
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