59 research outputs found

    Integrating Integrated Water Management

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    © 2014, Thomas Telford Services Ltd. All rights reserved. The water cycle is a contiguous system interconnected with human activities. Management has tended to be fragmented across anthropocentrically defined disciplines, potentially generating unintended negative consequences. The ecosystem approach and the ecosystem services framework emphasise interlinked, albeit often overlooked, benefits that the natural environment provides for people. This enables recognition and avoidance of potential ‘negative externalities’, identification of solutions optimising benefits across multiple services, and participation of wider constituencies of stakeholders. Systemic, outcome-based approaches are inherently economically efficient, yielding greater cumulative benefits for lower transaction costs by working with natural processes. The ecosystem approach establishes geographical and socio-economic contexts for management ecosystem service outcomes, providing a broader context in which to nest established water resource management methods. The ecosystem approach can also be applied at different scales and to diverse societal activities, internalising into them the value of natural processes. It is amenable to integration into catchment-scale considerations, yet does not present these activities as subsidiary to river basin planning. The addition of ecosystem services for options appraisal in preexisting decision-support tools adapts them to better address multi-benefit goals. Shifts are required in the policy and economic environment, but engineers have an important role in promoting, applying and innovating multibenefit solutions

    Potential Use of a Serpin from Arabidopsis for Pest Control

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    Although genetically modified (GM) plants expressing toxins from Bacillus thuringiensis (Bt) protect agricultural crops against lepidopteran and coleopteran pests, field-evolved resistance to Bt toxins has been reported for populations of several lepidopteran species. Moreover, some important agricultural pests, like phloem-feeding insects, are not susceptible to Bt crops. Complementary pest control strategies are therefore necessary to assure that the benefits provided by those insect-resistant transgenic plants are not compromised and to target those pests that are not susceptible. Experimental GM plants producing plant protease inhibitors have been shown to confer resistance against a wide range of agricultural pests. In this study we assessed the potential of AtSerpin1, a serpin from Arabidopsis thaliana (L). Heynh., for pest control. In vitro assays were conducted with a wide range of pests that rely mainly on either serine or cysteine proteases for digestion and also with three non-target organisms occurring in agricultural crops. AtSerpin1 inhibited proteases from all pest and non-target species assayed. Subsequently, the cotton leafworm Spodoptera littoralis Boisduval and the pea aphid Acyrthosiphon pisum (Harris) were fed on artificial diets containing AtSerpin1, and S. littoralis was also fed on transgenic Arabidopsis plants overproducing AtSerpin1. AtSerpin1 supplied in the artificial diet or by transgenic plants reduced the growth of S. littoralis larvae by 65% and 38%, respectively, relative to controls. Nymphs of A. pisum exposed to diets containing AtSerpin1 suffered high mortality levels (LC50 = 637 µg ml−1). The results indicate that AtSerpin1 is a good candidate for exploitation in pest control

    Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH3CHF2) from in situ and air archive observations

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    High frequency, in situ observations from 11 globally distributed sites for the period 1994–2014 and archived air measurements dating from 1978 onward have been used to determine the global growth rate of 1,1-difluoroethane (HFC-152a, CH3CHF2). These observations have been combined with a range of atmospheric transport models to derive global emission estimates in a top-down approach. HFC-152a is a greenhouse gas with a short atmospheric lifetime of about 1.5 years. Since it does not contain chlorine or bromine, HFC-152a makes no direct contribution to the destruction of stratospheric ozone and is therefore used as a substitute for the ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). The concentration of HFC-152a has grown substantially since the first direct measurements in 1994, reaching a maximum annual global growth rate of 0.84 ± 0.05 ppt yr−1 in 2006, implying a substantial increase in emissions up to 2006. However, since 2007, the annual rate of growth has slowed to 0.38 ± 0.04 ppt yr−1 in 2010 with a further decline to an annual average rate of growth in 2013–2014 of −0.06 ± 0.05 ppt yr−1. The annual average Northern Hemisphere (NH) mole fraction in 1994 was 1.2 ppt rising to an annual average mole fraction of 10.1 ppt in 2014. Average annual mole fractions in the Southern Hemisphere (SH) in 1998 and 2014 were 0.84 and 4.5 ppt, respectively. We estimate global emissions of HFC-152a have risen from 7.3 ± 5.6 Gg yr−1 in 1994 to a maximum of 54.4 ± 17.1 Gg yr−1 in 2011, declining to 52.5 ± 20.1 Gg yr−1 in 2014 or 7.2 ± 2.8 Tg-CO2 eq yr−1. Analysis of mole fraction enhancements above regional background atmospheric levels suggests substantial emissions from North America, Asia, and Europe. Global HFC emissions (so called “bottom up” emissions) reported by the United Nations Framework Convention on Climate Change (UNFCCC) are based on cumulative national emission data reported to the UNFCCC, which in turn are based on national consumption data. There appears to be a significant underestimate ( >  20 Gg) of “bottom-up” reported emissions of HFC-152a, possibly arising from largely underestimated USA emissions and undeclared Asian emissions

    High Climate Model Dependency of Pliocene Antarctic Ice-Sheet Predictions

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    The mid-Pliocene warm period provides a natural laboratory to investigate the long-term response of the Earth’s ice-sheets and sea level in a warmer-than-present-day world. Proxy data suggest that during the warm Pliocene, portions of the Antarctic ice-sheets, including West Antarctica could have been lost. Ice-sheet modelling forced by Pliocene climate model outputs is an essential way to improve our understanding of ice-sheets during the Pliocene. However, uncertainty exists regarding the degree to which results are model-dependent. Using climatological forcing from an international climate modelling intercomparison project, we demonstrate the high dependency of Antarctic ice-sheet volume predictions on the climate model-based forcing used. In addition, the collapse of the vulnerable marine basins of Antarctica is dependent on the ice-sheet model used. These results demonstrate that great caution is required in order to avoid making unsound statements about the nature of the Pliocene Antarctic ice-sheet based on model results that do not account for structural uncertainty in both the climate and ice sheet models

    The changing relationships between government bond yields and capitalisation rates: evidence from the UK, USA and Australia

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    Purpose – The purpose of this paper is to analyse the gap between government bonds (index-linked and long-dated) and real estate yields/capitalization rates over time for the UK, Australia and the USA. The global financial crisis was a sharp shock to real estate markets, and while interest rates and government bond yields fell in response around the world, real estate yields (cap rates) have risen. Design/methodology/approach – The absolute yield gap levels and their variation over time in the different countries are compared and linked to the theoretical reasons for the yield gap and, in particular, a changing real estate risk premium. Within this context, it assesses whether there have been structural breaks in long-term relationships during booms and busts based on autoregressive conditionally heteroscedastic (ARCH) models. Finally, the paper provides further insights by constructing statistical models of index-linked and long-dated yield gaps. Findings – The relationships between bond and property yields go through a traumatic time around the period of the global financial crisis. These changes are sufficiently strong to be statistically defined as “structural breaks” in the time series. The sudden switch in the yield gaps may have stimulated a greater appreciation of structural change in the property market. Research limitations/implications – The research focuses on the most transparent real estate markets in the world, but other countries with less developed markets may respond differently. Practical implications – The practical implications relate to how to value real estate yields relative to interest rates. Originality/value – This is the first paper that has compared international yield gaps over time and examined the role of the gap between index-linked government bonds and real estate yields. </jats:sec
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