73 research outputs found
Ecological risks of novel environmental crop technologies using phytoremediation as an example:
"Phytoremediation is the use of living plants, known as hyperaccumulators which absorb unusually large amounts of metals in comparison to other plants. The use of classical plant breeding and new molecular techniques offers great potential to develop crops with the ability to clean up polluted sites. While these technologies have gained widespread attention, prior to commercial development, there are risks that must be considered – only a few of which have received even modest examination. Therefore, the focus of this working paper is to explore specific risks associated with phytoremediation and suggest ways in which these risks can be managed so that new, novel, and innovative plant technologies may be applied to provide low cost and efficient environmental solutions. " Authors' AbstractPhytoextraction, Phytomining,
Incorporating project uncertainty in novel environmental biotechnologies: illustrated using phytoremediation
"Pollution of the environment by metals and organic contaminants is an intractable global problem, with cleanup costs running into billions of dollars using current engineering technologies. The availability of alternative, cheap and effective technologies would significantly improve the prospects of cleaning-up metal contaminated sites. Phytoremediation has been proposed as an economical and ‘green' method of exploiting plants to extract or degrade the contaminants in the soil. To date, the majority of phytoremediation efforts have been directed at leaping the biological, biochemical and agronomic hurdles to deliver a working technology, with scant attention to the economic outlook other than simple estimates of the cost advantages of phytoremediation over other techniques. In this paper we use a deterministic actuarial model to show that uncertainty in project success (the possibility that full clean up may not be realized) may significantly increase the perceived costs of remediation works for decision-makers." Authors' Abstractbiotechnology, Soil contaminants, Environmental remediation Economic aspects, Industrial crop technologies,
The Zero Age Main Sequence of WIMP burners
We modify a stellar structure code to estimate the effect upon the main
sequence of the accretion of weakly interacting dark matter onto stars and its
subsequent annihilation. The effect upon the stars depends upon whether the
energy generation rate from dark matter annihilation is large enough to shut
off the nuclear burning in the star. Main sequence WIMP burners look much like
protostars moving on the Hayashi track, although they are in principle
completely stable. We make some brief comments about where such stars could be
found, how they might be observed and more detailed simulations which are
currently in progress. Finally we comment on whether or not it is possible to
link the paradoxically young OB stars found at the galactic centre with WIMP
burners.Comment: 4 pages, 3 figs. Matches published versio
Dark Matter Capture in the First Stars: a Power Source and Limit on Stellar Mass
The annihilation of weakly interacting massive particles can provide an
important heat source for the first (Pop. III) stars, potentially leading to a
new phase of stellar evolution known as a "Dark Star". When dark matter (DM)
capture via scattering off of baryons is included, the luminosity from DM
annihilation may dominate over the luminosity due to fusion, depending on the
DM density and scattering cross-section. The influx of DM due to capture may
thus prolong the lifetime of the Dark Stars. Comparison of DM luminosity with
the Eddington luminosity for the star may constrain the stellar mass of zero
metallicity stars; in this case DM will uniquely determine the mass of the
first stars. Alternatively, if sufficiently massive Pop. III stars are found,
they might be used to bound dark matter properties.Comment: 19 pages, 4 figures, 3 Tables updated captions and graphs, corrected
grammer, and added citations revised for submission to JCA
A Profile Likelihood Analysis of the Constrained MSSM with Genetic Algorithms
The Constrained Minimal Supersymmetric Standard Model (CMSSM) is one of the
simplest and most widely-studied supersymmetric extensions to the standard
model of particle physics. Nevertheless, current data do not sufficiently
constrain the model parameters in a way completely independent of priors,
statistical measures and scanning techniques. We present a new technique for
scanning supersymmetric parameter spaces, optimised for frequentist profile
likelihood analyses and based on Genetic Algorithms. We apply this technique to
the CMSSM, taking into account existing collider and cosmological data in our
global fit. We compare our method to the MultiNest algorithm, an efficient
Bayesian technique, paying particular attention to the best-fit points and
implications for particle masses at the LHC and dark matter searches. Our
global best-fit point lies in the focus point region. We find many
high-likelihood points in both the stau co-annihilation and focus point
regions, including a previously neglected section of the co-annihilation region
at large m_0. We show that there are many high-likelihood points in the CMSSM
parameter space commonly missed by existing scanning techniques, especially at
high masses. This has a significant influence on the derived confidence regions
for parameters and observables, and can dramatically change the entire
statistical inference of such scans.Comment: 47 pages, 8 figures; Fig. 8, Table 7 and more discussions added to
Sec. 3.4.2 in response to referee's comments; accepted for publication in
JHE
Dark Matter Candidates: A Ten-Point Test
An extraordinarily rich zoo of non-baryonic Dark Matter candidates has been
proposed over the last three decades. Here we present a 10-point test that a
new particle has to pass, in order to be considered a viable DM candidate: I.)
Does it match the appropriate relic density? II.) Is it {\it cold}? III.) Is it
neutral? IV.) Is it consistent with BBN? V.) Does it leave stellar evolution
unchanged? VI.) Is it compatible with constraints on self-interactions? VII.)
Is it consistent with {\it direct} DM searches? VIII.) Is it compatible with
gamma-ray constraints? IX.) Is it compatible with other astrophysical bounds?
X.) Can it be probed experimentally?Comment: 29 pages, 12 figure
Ecological risks of novel environmental crop technologies using phytoremediation as an example
Phytoremediation is the use of living plants, known as hyperaccumulators which absorb unusually large amounts of metals in comparison to other plants. The use of classical plant breeding and new molecular techniques offers great potential to develop crops with the ability to clean up polluted sites. While these technologies have gained widespread attention, prior to commercial development, there are risks that must be considered – only a few of which have received even modest examination. Therefore, the focus of this working paper is to explore specific risks associated with phytoremediation and suggest ways in which these risks can be managed so that new, novel, and innovative plant technologies may be applied to provide low cost and efficient environmental solutions.-- Authors' AbstractNon-PRIFPRI1; PBSEPT
Ecological Risks of Novel Environmental Crop Technologies Using Phytoremediation as an Example
Phytoremediation is the use of living plants, known as hyperaccumulators which absorb
unusually large amounts of metals in comparison to other plants. The use of classical
plant breeding and new molecular techniques offers great potential to develop crops with
the ability to clean up polluted sites. While these technologies have gained widespread
attention, prior to commercial development, there are risks that must be considered – only
a few of which have received even modest examination. Therefore, the focus of this
working paper is to explore specific risks associated with phytoremediation and suggest
ways in which these risks can be managed so that new, novel, and innovative plant
technologies may be applied to provide low cost and efficient environmental solutions
Incorporating Project Uncertainty in Novel Environment Biotechnologies: Illustrated Using Phytoremediation
Pollution of the environment by metals and organic contaminants is an intractable
global problem, with cleanup costs running into billions of dollars using current
engineering technologies. The availability of alternative, cheap and effective
technologies would significantly improve the prospects of cleaning-up metal
contaminated sites. Phytoremediation has been proposed as an economical and ‘green’
method of exploiting plants to extract or degrade the contaminants in the soil. To date,
the majority of phytoremediation efforts have been directed at leaping the biological,
biochemical and agronomic hurdles to deliver a working technology, with scant attention
to the economic outlook other than simple estimates of the cost advantages of
phytoremediation over other techniques. In this paper we use a deterministic actuarial
model to show that uncertainty in project success (the possibility that full clean up may
not be realized) may significantly increase the perceived costs of remediation works for
decision-makers
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