153 research outputs found
No net loss of what, for whom?: stakeholder perspectives to Biodiversity Offsetting in England
Market-based instruments (MBIs) have emerged as a popular approach to balance development and conservation objectives. However, their ability to accomplish this is often beset by poor implementation in practice. This is testament to a widening gap between the rate of policy development and implementation of MBIs and the maturity of research and evaluation on their design, and impact on affected stakeholders. Within this context, this paper examines multi-stakeholder perspectives to the adoption of Biodiversity Offsetting in England, an instrument designed to enable biodiversity losses in one place to be compensated through conservation improvements elsewhere. Analysis reveals issues associated with social and ecological compensation of biodiversity loss. Findings suggest that there is a need for a broader consideration of issues surrounding distributive justice, access to nature and the status of ownership over sites of common heritage when accounting for biodiversity loss and its compensation. This message is salient to both the study context as well as the burgeoning international practice of Biodiversity Offsetting
Stimulating environmental degradation: a global study of resource use in cocoa, coffee, tea and tobacco supply chains
Industrial Ecolog
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When defining boundaries for nexus analysis, let the data speak
A policy and research agenda has emerged in recent years to understand the interconnected risks natural resource systems face and drive. The so-called âFood-Energy-Waterâ (FEW) nexus has served as a focal point for the conceptual, theoretical and empirical development of this agenda. This special issue provides an opportunity to reflect on whether natural resource use, as viewed through the FEW-nexus lens, provides a useful basis for guiding integrated environmental management.
Within this piece, we describe how the partiality of the FEW-nexus overlooks major pathways of resource use (i) within the food system and (ii) across the wider burden of human activity. As a result, we argue FEW-centric analysis is more likely to disguise rather than reveal key opportunities for integrated environmental management.Cambridge Trust (Vice-Chancellor's Award
A pseudoclass-AB telescopic-cascode operational amplifier
ABSTRACT A novel class-AB architecture for single-stage operational amplifiers is presented. The structure employs a switchedcapacitor level shifter to provide a signal-dependent current in the current source of the common-source amplifier. Applying this pseudo-class-AB approach to a telescopic-cascode op-amp enhances the effective values of the slew rate and the transconductance and thus the op-amp speed
Inhibitor tolerance and flocculation of a yeast strain suitable for second generation bioethanol production
Background: Robust second generation bioethanol processes require
microorganisms able to ferment inhibitory lignocellullosic
hydrolysates. In this study, the inhibitor tolerance and flocculation
characteristics of Saccharomyces cerevisiae CCUG53310 were evaluated
in comparison with S. cerevisiae CBS8066. Results: The flocculating
strain CCUG53310 could rapidly ferment all hexoses in dilute acid
spruce hydrolysate, while CBS8066 was strongly inhibited in this
medium. In synthetic inhibitory media, CCUG53310 was more tolerant to
carboxylic acids and furan aldehydes, but more sensitive than CBS8066
to phenolic compounds. Despite the higher tolerance, the increase in
expression of the YAP1, ATR1 and FLR1 genes, known to confer resistance
to lignocellulose-derived inhibitors, was generally smaller in
CCUG53310 than in CBS8066 in inhibitory media. The flocculation of
CCUG53310 was linked to the expression of FLO8, FLO10 and one or more
of FLO1, FLO5 or FLO9. Flocculation depended on cell wall proteins and
Ca2+ ions, but was almost unaffected by other compounds and pH values
typical for lignocellulosic media. Conclusions: S. cerevisiae CCUG53310
can be characterised as being very robust, with great potential for
industrial fermentation of lignocellulosic hydrolysates relatively low
in phenolic inhibitors
Analysis of the wave propagation properties of a periodic array of rigid cylinders perpendicular to a finite impedance surface
The effect of the presence of a finite impedance surface on the wave
propagation properties of a two-dimensional periodic array of rigid cylinders
with their axes perpendicular to the surface is both numerically and
experimentally analyzed in this work. In this realistic situation both the
incident and the scattered waves interact with these two elements, the surface
and the array. The interaction between the excess attenuation effect, due to
the destructive interference produced by the superposition of the incident wave
and the reflected one by the surface, and the bandgap, due to the periodicity
of the array, is fundamental for the design of devices to control the
transmission of waves based on periodic arrays. The most obvious application is
perhaps the design of Sonic Crystals Noise Barriers. Two different finite
impedance surfaces have been analyzed in the work in order to observe the
dependence of the wave propagation properties on the impedance of the surface
Genetic changes that increase 5-hydroxymethyl furfural resistance in ethanol-producing Escherichia coli LY180
The ability of a biocatalyst to tolerate furan inhibitors present in hemicellulose hydrolysates is important for the production of renewable chemicals. This study shows EMFR9, a furfural-tolerant mutant of ethanologenic E. coli LY180, has also acquired tolerance to 5-hydroxymethyl furfural (5-HMF). The mechanism of action of 5-HMF and furfural appear similar. Furan tolerance results primarily from lower expression of yqhD and dkgA, two furan reductases with a low Km for NADPH. Furan tolerance was also increased by adding plasmids encoding a NADPH/NADH transhydrogenase (pntAB). Together, these results support the hypothesis that the NADPH-dependent reduction of furans by YqhD and DkgA inhibits growth by competing with biosynthesis for this limiting cofactor
Exploring evolution of maximum growth rates in plankton
Evolution has direct and indirect consequences on speciesâspecies interactions and the environment. However, Earth systems models describing planktonic activity invariably fail to explicitly consider organism evolution. Here we simulate the evolution of the single most important physiological characteristic of any organism as described in modelsâits maximum growth rate (ÎŒm). Using a low-computational-cost approach, we incorporate the evolution of ÎŒm for each of the plankton components in a simple Nutrient-Phytoplankton-Zooplankton -style model such that the fitness advantages and disadvantages in possessing a high ÎŒm evolve to become balanced. The model allows an exploration of parameter ranges leading to stresses, which drive the evolution of ÎŒm. In applications of the method we show that simulations of climate change give very different projections when the evolution of ÎŒm is considered. Thus, production may decline as evolution reshapes growth and trophic dynamics. Additionally, predictions of extinction of species may be overstated in simulations lacking evolution as the ability to evolve under changing environmental conditions supports evolutionary rescue. The model explains why organisms evolved for mature ecosystems (e.g. temperate summer, reliant on local nutrient recycling or mixotrophy), express lower maximum growth rates than do organisms evolved for immature ecosystems (e.g. temperate spring, high resource availability)
Improving simultaneous saccharification and co-fermentation of pretreated wheat straw using both enzyme and substrate feeding
<p>Abstract</p> <p>Background</p> <p>Simultaneous saccharification and co-fermentation (SSCF) has been recognized as a feasible option for ethanol production from xylose-rich lignocellulosic materials. To reach high ethanol concentration in the broth, a high content of water-insoluble solids (WIS) is needed, which creates mixing problems and, furthermore, may decrease xylose uptake. Feeding of substrate has already been proven to give a higher xylose conversion than a batch SSCF. In the current work, enzyme feeding, in addition to substrate feeding, was investigated as a means of enabling a higher WIS content with a high xylose conversion in SSCF of a xylose-rich material. A recombinant xylose-fermenting strain of <it>Saccharomyces cerevisiae </it>(TMB3400) was used for this purpose in fed-batch SSCF experiments of steam-pretreated wheat straw.</p> <p>Results</p> <p>By using both enzyme and substrate feeding, the xylose conversion in SSCF could be increased from 40% to 50% in comparison to substrate feeding only. In addition, by this design of the feeding strategy, it was possible to process a WIS content corresponding to 11% in SSCF and obtain an ethanol yield on fermentable sugars of 0.35 g g<sup>-1</sup>.</p> <p>Conclusion</p> <p>A combination of enzyme and substrate feeding was shown to enhance xylose uptake by yeast and increase overall ethanol yield in SSCF. This is conceptually important for the design of novel SSCF processes aiming at high-ethanol titers. Substrate feeding prevents viscosity from becoming too high and thereby allows a higher total amount of WIS to be added in the process. The enzyme feeding, furthermore, enables keeping the glucose concentration low, which kinetically favors xylose uptake and results in a higher xylose conversion.</p
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