Showing papers by "University of East Anglia published in 2008"

Quantum dots versus organic dyes as fluorescent labels

Abstract: Suitable labels are at the core of Luminescence and fluorescence imaging and sensing. One of the most exciting, yet also controversial, advances in label technology is the emerging development of quantum dots (QDs)--inorganic nanocrystals with unique optical and chemical properties but complicated surface chemistry--as in vitro and in vivo fluorophores. Here we compare and evaluate the differences in physicochemical properties of common fluorescent labels, focusing on traditional organic dyes and QDs. Our aim is to provide a better understanding of the advantages and limitations of both classes of chromophores, to facilitate label choice and to address future challenges in the rational design and manipulation of QD labels.

Tipping elements in the Earth's climate system

Abstract: The term "tipping point" commonly refers to a critical threshold at which a tiny perturbation can qualitatively alter the state or development of a system. Here we introduce the term "tipping element" to describe large-scale components of the Earth system that may pass a tipping point. We critically evaluate potential policy-relevant tipping elements in the climate system under anthropogenic forcing, drawing on the pertinent literature and a recent international workshop to compile a short list, and we assess where their tipping points lie. An expert elicitation is used to help rank their sensitivity to global warming and the uncertainty about the underlying physical mechanisms. Then we explain how, in principle, early warning systems could be established to detect the proximity of some tipping points.

A European daily high-resolution gridded data set of surface temperature and precipitation for 1950-2006

Abstract: We present a European land-only daily high-resolution gridded data set for precipitation and minimum, maximum, and mean surface temperature for the period 1950-2006. This data set improves on previous products in its spatial resolution and extent, time period, number of contributing stations, and attention to finding the most appropriate method for spatial interpolation of daily climate observations. The gridded data are delivered on four spatial resolutions to match the grids used in previous products as well as many of the rotated pole Regional Climate Models (RCMs) currently in use. Each data set has been designed to provide the best estimate of grid box averages rather than point values to enable direct comparison with RCMs. We employ a three-step process of interpolation, by first interpolating the monthly precipitation totals and monthly mean temperature using three-dimensional thin-plate splines, then interpolating the daily anomalies using indicator and universal kriging for precipitation and kriging with an external drift for temperature, then combining the monthly and daily estimates. Interpolation uncertainty is quantified by the provision of daily standard errors for every grid square. The daily uncertainty averaged across the entire region is shown to be largely dependent on the season and number of contributing observations. We examine the effect that interpolation has on the magnitude of the extremes in the observations by calculating areal reduction factors for daily maximum temperature and precipitation events with return periods up to 10 years. Copyright 2008 by the American Geophysical Union.

Volcanic carbon dioxide vents show ecosystem effects of ocean acidification

Abstract: A high-profile Royal Society report in 2005, followed by similar reports worldwide, high-lighted the fact that relatively little is known about the ecosystem effects of ocean acidification. Work to date has been largely limited to short-term experiments on isolated aspects of marine communities. Hall-Spencer et al. adopted an alternative approach, tracking the response to CO2 release from volcanic vent sites off the island of Ischia in the Bay of Naples, where ocean acidification has prevailed perhaps for centuries. Typical rocky shore communities rich in calcareous organisms thrive at normal pH, shifting to communities lacking scleractinian corals and low in sea urchin and algal numbers at low pH. The results show that such sites can act as natural experiments against which to test laboratory and modelled predictions of the effects of ocean acidification. The ecological impact of ocean acidification as a result of climate change is difficult to predict. A natural CO2 venting site is used here to demonstrate the shifts occurring in a rocky shore marine community as a result of a pH gradient. The atmospheric partial pressure of carbon dioxide ( ) will almost certainly be double that of pre-industrial levels by 2100 and will be considerably higher than at any time during the past few million years1. The oceans are a principal sink for anthropogenic CO2 where it is estimated to have caused a 30% increase in the concentration of H+ in ocean surface waters since the early 1900s and may lead to a drop in seawater pH of up to 0.5 units by 2100 (refs 2, 3). Our understanding of how increased ocean acidity may affect marine ecosystems is at present very limited as almost all studies have been in vitro, short-term, rapid perturbation experiments on isolated elements of the ecosystem4,5. Here we show the effects of acidification on benthic ecosystems at shallow coastal sites where volcanic CO2 vents lower the pH of the water column. Along gradients of normal pH (8.1–8.2) to lowered pH (mean 7.8–7.9, minimum 7.4–7.5), typical rocky shore communities with abundant calcareous organisms shifted to communities lacking scleractinian corals with significant reductions in sea urchin and coralline algal abundance. To our knowledge, this is the first ecosystem-scale validation of predictions that these important groups of organisms are susceptible to elevated amounts of . Sea-grass production was highest in an area at mean pH 7.6 (1,827 μatm ) where coralline algal biomass was significantly reduced and gastropod shells were dissolving due to periods of carbonate sub-saturation. The species populating the vent sites comprise a suite of organisms that are resilient to naturally high concentrations of and indicate that ocean acidification may benefit highly invasive non-native algal species. Our results provide the first in situ insights into how shallow water marine communities might change when susceptible organisms are removed owing to ocean acidification.

The Determinants of Rural Livelihood Diversification in Developing Countries

Abstract: The diversity of rural livelihoods in low income developing countries is receiving increased attention in discussions about rural poverty reduction. This paper explores just one facet of livelihood diversity, namely the reasons for households to adopt multiple livelihood strategies. The distinction is made between diversification of necessity and diversification by choice. Six determinants of diversification are considered in the light of that distinction, and these are seasonality, risk, labour markets, credit markets, asset strategies, and coping strategies. The paper concludes that under the precarious conditions that characterise rural survival in many low income countries, diversification has positive attributes for livelihood security that outweigh negative connotations it may possess. Policy should facilitate rather than inhibit diversity. Diverse rural livelihoods are less vulnerable than undiversified ones.

Speciation, hybrid zones and phylogeography - or seeing genes in space and time.

Abstract: The origins and development of the study of speciation, hybrid zones and phylogeography are outlined using evolutionary iconography. This traces the ideas in this field from Lamarck and Darwin through to the present as represented in diagrams and figures. A ‘tree of trees’ summarizes this growth and current vitality. The new facility to use various DNA sequences from nuclear, mitochondrial and chloroplast genomes to determine genetic variation throughout a species range is examined particularly. There is great genomic subdivision across species distributions, which can be interpreted in the light of the recent demonstrations of severe palaeoclimatic oscillations. Refugia and postglacial colonization routes are proposed for several organisms across Europe. The role of geography in speciation through the Pleistocene is considered. These emerging principles and analyses are applied to data available on a variety of organisms in other regions of the world, such as the Arctic, North America and the Tropics, and including the progress of Homo sapiens through the last ice age. Some suggestions are made for future research directions.

A 60 000 year Greenland stratigraphic ice core chronology

Abstract: . The Greenland Ice Core Chronology 2005 (GICC05) is a time scale based on annual layer counting of high-resolution records from Greenland ice cores. Whereas the Holocene part of the time scale is based on various records from the DYE-3, the GRIP, and the NorthGRIP ice cores, the glacial part is solely based on NorthGRIP records. Here we present an 18 ka extension of the time scale such that GICC05 continuously covers the past 60 ka. The new section of the time scale places the onset of Greenland Interstadial 12 (GI-12) at 46.9±1.0 ka b2k (before year AD 2000), the North Atlantic Ash Zone II layer in GI-15 at 55.4±1.2 ka b2k, and the onset of GI-17 at 59.4±1.3 ka b2k. The error estimates are derived from the accumulated number of uncertain annual layers. In the 40–60 ka interval, the new time scale has a discrepancy with the Meese-Sowers GISP2 time scale of up to 2.4 ka. Assuming that the Greenland climatic events are synchronous with those seen in the Chinese Hulu Cave speleothem record, GICC05 compares well to the time scale of that record with absolute age differences of less than 800 years throughout the 60 ka period. The new time scale is generally in close agreement with other independently dated records and reference horizons, such as the Laschamp geomagnetic excursion, the French Villars Cave and the Austrian Kleegruben Cave speleothem records, suggesting high accuracy of both event durations and absolute age estimates.

Impacts of atmospheric anthropogenic nitrogen on the open ocean.

Abstract: Increasing quantities of atmospheric anthropogenic fixed nitrogen entering the open ocean could account for up to about a third of the ocean's external (nonrecycled) nitrogen supply and up to 3% of the annual new marine biological production, 0.3 petagram of carbon per year. This input could account for the production of up to 1.6 teragrams of nitrous oxide (N2O) per year. Although 10% of the ocean's drawdown of atmospheric anthropogenic carbon dioxide may result from this atmospheric nitrogen fertilization, leading to a decrease in radiative forcing, up to about two-thirds of this amount may be offset by the increase in N2O emissions. The effects of increasing atmospheric nitrogen deposition are expected to continue to grow in the future.

Phase I Clinical Trial of a Selective Inhibitor of CYP17, Abiraterone Acetate, Confirms That Castration-Resistant Prostate Cancer Commonly Remains Hormone Driven

Abstract: Purpose Studies indicate that castration-resistant prostate cancer (CRPC) remains driven by ligand-dependent androgen receptor (AR) signaling. To evaluate this, a trial of abiraterone acetate—a potent, selective, small-molecule inhibitor of cytochrome P (CYP) 17, a key enzyme in androgen synthesis—was pursued. Patients and Methods Chemotherapy-naive men (n = 21) who had prostate cancer that was resistant to multiple hormonal therapies were treated in this phase I study of once-daily, continuous abiraterone acetate, which escalated through five doses (250 to 2,000 mg) in three-patient cohorts. Results Abiraterone acetate was well tolerated. The anticipated toxicities attributable to a syndrome of secondary mineralocorticoid excess—namely hypertension, hypokalemia, and lower-limb edema—were successfully managed with a mineralocorticoid receptor antagonist. Antitumor activity was observed at all doses; however, because of a plateau in pharmacodynamic effect, 1,000 mg was selected for cohort expansion (n = 9)...

Are flood victims more concerned about climate change than other people? The role of direct experience in risk perception and behavioural response

Abstract: Climate change is a threat to human health and life, both now and in the future. Despite this, studies show that the public typically do not consider the issue a priority concern or a direct, personal threat. Furthermore, few are taking any preventive or protective action. Previous studies identify direct experience as a major influence on risk perception, learning and action. Drawing on such evidence, this paper focuses on the intangibility of climate change as a key impediment to personal engagement and explores whether relevant experiences of flooding and air pollution influence individuals' knowledge, attitudes, risk perception and behavioural responses to climate change. Perhaps surprisingly, interviews and a survey conducted in the south of England indicate flood victims differ very little from other participants in their understanding of and responses to climate change, but that experience of air pollution does significantly affect perceptions of and behavioural responses to climate change. Air pollution victims are no more likely to cite pollution as a cause of climate change than non‐victims; but they do have higher pro‐environmental values. Respondents with these values are significantly more likely to consider climate change a salient risk and to take action in response to it. Therefore the relationship between air pollution experience and responses to climate change may be indirect and mediated by environmental values. The paper concludes by highlighting implications of this research for developing climate change policies and strategies for public engagement.

Global distribution of atmospheric phosphorus sources, concentrations and deposition rates, and anthropogenic impacts

Abstract: A worldwide compilation of atmospheric total phosphorus (TP) and phosphate (PO4) concentration and deposition flux observations are combined with transport model simulations to derive the global distribution of concentrations and deposition fluxes of TP and PO4. Our results suggest that mineral aerosols are the dominant source of TP on a global scale (82%), with primary biogenic particles (12%) and combustion sources (5%) important in nondusty regions. Globally averaged anthropogenic inputs are estimated to be similar to 5 and 15% for TP and PO4, respectively, and may contribute as much as 50% to the deposition over the oligotrophic ocean where productivity may be phosphorus-limited. There is a net loss of TP from many (but not all) land ecosystems and a net gain of TP by the oceans (560 Gg P a(-1)). More measurements of atmospheric TP and PO4 will assist in reducing uncertainties in our understanding of the role that atmospheric phosphorus may play in global biogeochemistry.

Phylogenetic analysis of community assembly and structure over space and time.

Abstract: Evolutionary ecologists are increasingly combining phylogenetic data with distributional and ecological data to assess how and why communities of species differ from random expectations for evolutionary and ecological relatedness. Of particular interest have been the roles of environmental filtering and competitive interactions, or alternatively neutral effects, in dictating community composition. Our goal is to place current research within a dynamic framework, specifically using recent phylogenetic studies from insular environments to provide an explicit spatial and temporal context. We compare communities over a range of evolutionary, ecological and geographic scales that differ in the extent to which speciation and adaptation contribute to community assembly and structure. This perspective allows insights into the processes that can generate community structure, as well as the evolutionary dynamics of community assembly.

Does public policy support or undermine climate change adaptation? Exploring policy interplay across different scales of governance

Abstract: Policy makers have now recognised the need to integrate thinking about climate change into all areas of public policy making. However, the discussion of ‘climate policy integration’ has tended to focus on mitigation decisions mostly taken at international and national levels. Clearly, there is also a more locally focused adaptation dimension to climate policy integration, which has not been adequately explored by academics or policy makers. Drawing on a case study of the UK, this paper adopts both a top-down and a bottom-up perspective to explore how far different sub-elements of policies within the agriculture, nature conservation and water sectors support or undermine potential adaptive responses. The top-down approach, which assumes that policies set explicit aims and objectives that are directly translated into action on the ground, combines a content analysis of policy documents with interviews with policy makers. The bottom-up approach recognises the importance of other actors in shaping policy implementation and involves interviews with actors in organisations within the three sectors. This paper reveals that neither approach offers a complete picture of the potentially enabling or constraining effects of different policies on future adaptive planning, but together they offer new perspectives on climate policy integration. These findings inform a discussion on how to implement climate policy integration, including auditing existing policies and ‘climate proofing’ new ones so they support rather than hinder adaptive planning.

Ecosystem services and economic theory: integration for policy-relevant research.

Abstract: It has become essential in policy and decision-making circles to think about the economic benefits (in addition to moral and scientific motivations) humans derive from well-functioning ecosystems. The concept of ecosystem services has been developed to address this link between ecosystems and human welfare. Since policy decisions are often evaluated through cost–benefit assessments, an economic analysis can help make ecosystem service research operational. In this paper we provide some simple economic analyses to discuss key concepts involved in formalizing ecosystem service research. These include the distinction between services and benefits, understanding the importance of marginal ecosystem changes, formalizing the idea of a safe minimum standard for ecosystem service provision, and discussing how to capture the public benefits of ecosystem services. We discuss how the integration of economic concepts and ecosystem services can provide policy and decision makers with a fuller spectrum of information for making conservation–conversion trade-offs. We include the results from a survey of the literature and a questionnaire of researchers regarding how ecosystem service research can be integrated into the policy process. We feel this discussion of economic concepts will be a practical aid for ecosystem service research to become more immediately policy relevant.

The cost-effectiveness of biodiversity surveys in tropical forests

Abstract: The identification of high-performance indicator taxa that combine practical feasibility and ecological value requires an understanding of the costs and benefits of surveying different taxa. We present a generic and novel framework for identifying such taxa, and illustrate our approach using a large-scale assessment of 14 different higher taxa across three forest types in the Brazilian Amazon, estimating both the standardized survey cost and the ecological and biodiversity indicator value for each taxon. Survey costs varied by three orders of magnitude, and dung beetles and birds were identified as especially suitable for evaluating and monitoring the ecological consequences of habitat change in our study region. However, an exclusive focus on such taxa occurs at the expense of understanding patterns of diversity in other groups. To improve the cost-effectiveness of biodiversity research we encourage a combination of clearer research goals and the use of an objective evidence-based approach to selecting study taxa.

The Ecosystem Services Framework and Natural Capital Conservation

Abstract: Work at the interface of ecology and economics has inspired a major transformation in the way people think about the environment. Increasingly, ecosystems are seen as capital assets, with the potential to generate a stream of vital life-support services meriting careful evaluation and investment. We first present the concepts underpinning the ecosystem services framework (ESF), laying out the scope and limitations of the approach. We then describe the major challenges in making the ESF operational: (i) detailed information at scales relevant to decision-making; (ii) practical know-how in the process of institutional design & implementation; and (iii) compelling models of success in which economic incentives are aligned with conservation. We close with a brief review of pioneering experiments now underway worldwide, which illustrate how these challenges can be overcome.

Inhaled Anticholinergics and Risk of Major Adverse Cardiovascular Events in Patients With Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis

Abstract: Context Inhaled anticholinergics (ipratropium bromide or tiotropium bromide) are widely used in patients with chronic obstructive pulmonary disease (COPD) but their effect on the risk of cardiovascular outcomes is unknown. Objective To ascertain the cardiovascular risks of inhaled anticholinergics, including cardiovascular death, myocardial infarction (MI), and stroke. Data Sources Systematic searches were conducted on March 19, 2008, of relevant articles in MEDLINE, the Cochrane Database of systematic reviews, regulatory authority Web sites in the United States and the United Kingdom, and manufacturers' trial registries with no date restrictions. Study Selection Randomized controlled trials of any inhaled anticholinergic for treatment of COPD that had at least 30 days of treatment and reported on cardiovascular events. Data Extraction The primary outcome was a composite of cardiovascular death, MI, or stroke. The secondary outcome was all-cause mortality. Relative risks (RRs) were estimated using fixed-effects models and statistical heterogeneity was estimated with the I2 statistic. Data Synthesis After a detailed screening of 103 articles, 17 trials enrolling 14 783 patients were analyzed. Follow-up duration ranged from 6 weeks to 5 years. Cardiovascular death, MI, or stroke occurred in 135 of 7472 patients (1.8%) receiving inhaled anticholinergics and 86 of 7311 patients (1.2%) receiving control therapy (RR, 1.58 [95% confidence interval {CI}, 1.21-2.06]; P 6 months) confirmed the significantly increased risk of cardiovascular death, MI, or stroke (2.9% of patients treated with anticholinergics vs 1.8% of the control patients; RR, 1.73 [95%CI, 1.27-2.36]; P Conclusion Inhaled anticholinergics are associated with a significantly increased risk of cardiovascular death, MI, or stroke among patients with COPD.

Deep sequencing of tomato short RNAs identifies microRNAs targeting genes involved in fruit ripening.

Abstract: In plants there are several classes of 21–24-nt short RNAs that regulate gene expression. The most conserved class is the microRNAs (miRNAs), although some miRNAs are found only in specific species. We used high-throughput pyrosequencing to identify conserved and nonconserved miRNAs and other short RNAs in tomato fruit and leaf. Several conserved miRNAs showed tissue-specific expression, which, combined with target gene validation results, suggests that miRNAs may play a role in fleshy fruit development. We also identified four new nonconserved miRNAs. One of the validated targets of a novel miRNA is a member of the CTR family involved in fruit ripening. However, 62 predicted targets showing near perfect complementarity to potential new miRNAs did not validate experimentally. This suggests that target prediction of plant short RNAs could have a high false-positive rate and must therefore be validated experimentally. We also found short RNAs from a Solanaceae-specific foldback transposon, which showed a miRNA/miRNA*-like distribution, suggesting that this element may function as a miRNA gene progenitor. The other Solanaceae-specific class of short RNA was derived from an endogenous pararetrovirus sequence inserted into the tomato chromosomes. This study opens a new avenue in the field of fleshy fruit biology by raising the possibility that fruit development and ripening may be under miRNA regulation.

Environmental determinants of active travel in youth: A review and framework for future research

Abstract: Many youth fail to meet the recommended guidelines for physical activity. Walking and cycling, forms of active travel, have the potential to contribute significantly towards overall physical activity levels. Recent research examining the associations between physical activity and the environment has shown that environmental factors play a role in determining behaviour in children and adolescents. However, links between the environment and active travel have received less attention. Twenty four studies were identified which examined the associations between the environment (perceived or objectively measured) and active travel among youth aged 5–18 years. Findings were categorised according to the location of the environmental measure examined; attributes of the neighbourhood, destination and the route between home and destination. Results from the reviewed studies indicated that youth active travel is positively associated with social interactions, facilities to assist active travel and urban form in the neighbourhood as well as shorter route length and road safety en-route. A conceptual framework is presented which highlights the associations between active travel behaviours and environmental factors, drawing upon both existing and hypothesised relationships. We provide a review of the available literature and present a novel theoretical framework that integrates the environment into the wider decision making process around travel choices for children and adolescents. Further work should explore associations where gaps in understanding have been identified, and account for the main moderators of behaviour so hypothesised associations can be confirmed.

The Governance of Sustainable Development: Taking Stock and Looking Forwards.

Abstract: The number of books and papers bearing the terms ‘sustainable development’ and ‘governance’ in their titles has grown exponentially in the last decade or so. The main purpose of this paper is to explore what meanings have been attached to these two essentially contested terms and to assess the extent to which the material on them constitutes an important, coherent, and cumulative body of scholarship. The first half explores the existing literatures on the two terms, and draws out some of the main similarities and differences. Drawing on papers that have been published in this journal over the last decade or so, the second half focuses on the attempts that have been made to build empirical and/or theoretical bridges between the two terms. The concluding section identifies a number of key themes and explores future research needs in what is evidently a vibrant and highly policy-relevant area of environmental social science research.

Modeling CO2 Emission Allowance Prices and Derivatives: Evidence from the European Trading Scheme

Abstract: This paper studies the three main markets for emission allowances within the European Union Emissions Trading Scheme (EU ETS): Powernext, Nord Pool and European Climate Exchange (ECX). The analysis suggests that the prohibition of banking of emission allowances between distinct phases of the EU ETS has significant implications in terms of futures pricing. Motivated by these findings, we develop an empirically and theoretically valid framework for the pricing and hedging of intra-phase and inter-phase futures and options on futures, respectively.

Primary submicron marine aerosol dominated by insoluble organic colloids and aggregates

Abstract: The chemical properties of sea-spray aerosol particles produced by artificially generated bubbles using oceanic waters were investigated during a phytoplankton bloom in the North Atlantic. Spray pa ...